SEO Fundamentals
What SEO is, how search engines work, and the vocabulary everything else assumes. Level 0 of the free SEO course, with all 12 lessons.
By the end of Level 0 you will be able to explain what happens between publishing a page and Google showing it to someone, without reaching for metaphors. That mental model is the tool you use in every later level to decide which piece of SEO work deserves your time and which is noise.
The mistake almost everyone makes here is treating SEO as a list of tricks rather than as a system of three independent stages. A page can be beautifully written and never appear, because Googlebot never crawled it. A different page can be crawled daily and stay out of the index, because Google decided it duplicates something it already holds. A third can sit in the index and earn no visits, because it competes for a query whose search intent it does not serve. Three different problems, three different fixes.
Anyone who blurs those stages ends up rewriting title tags for months to solve a crawling problem. That is why this level starts with the mechanism instead of the tactics. Without the mechanism, every piece of advice you read afterwards is an instruction with no context, and you have no way to judge it.
The twelve lessons in Level 0 fit into one unhurried week. There is nothing to memorise. There is a model to understand and an audit to run at the end to prove you understood it.
What this level covers
- Telling crawling, indexing and ranking apart, and knowing which of the three stages is failing when a page does not show up in Google.
- Sorting any query into one of the four search intent types and picking the content format that matches it.
- Reading a full 2026 search results page and estimating how much organic traffic is genuinely left before you invest in a keyword.
- Reading E-E-A-T and the Quality Rater Guidelines for what they are, without the folklore about scores that do not exist.
- Running keyword research from zero with a repeatable method instead of by inspiration.
- Assembling a minimum tool stack and finishing your first SEO audit in 90 minutes.
Crawling, indexing and ranking are three separate stages
Google works in three stages that happen at different moments and can fail independently. In the first, crawling, the Google robot called Googlebot discovers a URL through a link or a sitemap and downloads its HTML. In the second, indexing, Google processes that HTML, runs the JavaScript if it needs to, interprets the content and decides whether to store it in the index. In the third, ranking, Google compares already-indexed pages and orders the ones it considers relevant to a specific query.
The practical consequence is that diagnosis always follows that order. If a page is not indexed, the colour of a button and the density of a keyword are irrelevant. The URL Inspection tool in Google Search Console answers the right question: it says whether Google knows the URL, when Googlebot last fetched it, and whether it is in the index.
Crawling is also neither free nor unlimited. Google gives each site a finite amount of attention, and a site that spends it on duplicate URLs, endless pagination or filter parameters leaves the pages that matter uncrawled. On a small site this is rarely the bottleneck. On an ecommerce store with tens of thousands of filter-generated URLs, it is the first thing to look at.
Search intent decides the format before the words matter
Search intent is the real goal behind a query typed into Google, and it settles which page format can rank long before the wording of the text matters. The four classic categories are informational (I want to know), navigational (I want to reach a specific site), transactional (I want to buy or act) and commercial investigation (I want to compare before deciding).
The typical failure is not picking the wrong keyword. It is picking the right keyword and serving the wrong format. A query Google answers with comparisons and roundups will not be won by a product page, however good the product page is. That page is not competing at a disadvantage; it is competing in a different category.
There is a cheap way to verify intent before writing anything, and it is to look at what Google already rewards. Open the query, look at what kind of pages hold the top ten organic results, and look at which blocks Google has placed around them. If all ten results are long guides, the answer to that query is a long guide. That reading takes two minutes and saves weeks of misdirected work.
The first screen of a results page is no longer ten links
A Google results page in 2026 splits its first screen between generated answers, Google’s own blocks and organic results, in that order of prominence. AI overviews, featured snippets, the related questions block, local packs and shopping units push the first blue link further down on a growing share of queries.
That changes the arithmetic of keyword research. The useful question is no longer how many people search a term, but how much of that demand ever leaves the results page. Similarweb’s clickstream analysis for January to April 2026 found that 68.01% of Google searches in the United States ended without a click. Zero-click behaviour is not an anomaly; it is the majority case.
The sensible response is not to abandon informational queries but to split the effort. Commercial and transactional queries still produce clicks, because the answer does not fit in a summary. Informational queries are how Google and the answer engines come to cite you, which builds recognition even when it does not produce an immediate visit.
Five common beliefs and what actually holds
| Widespread belief | What actually holds | What to do in Level 0 |
|---|---|---|
| If the page is published, Google has it | Publishing only makes crawling possible; indexing is a separate decision Google makes | Check the real status in Google Search Console URL Inspection |
| E-E-A-T is a score Google assigns to each site | E-E-A-T is an evaluation criterion described in the Quality Rater Guidelines, not a computed metric | Read what the Quality Rater Guidelines say before chasing a number that does not exist |
| A core update penalises the sites that drop | A core update reorders overall assessment; a drop can happen with no violation at all | Separate a reordering drop from a manual action before changing anything |
| More search volume means more traffic | Volume counts queries, not the clicks left over after the blocks that occupy the results page | Look at the real results page for each term before it enters the plan |
| Internal linking is a detail to tidy up at the end | Internal linking steers crawling and spreads relevance across sections | Draw the section structure before writing the first page |
The 12 lessons in this level
- What SEO Actually Is in 2026
- How Search Engines Work: Crawling, Indexing, Ranking
- Search Intent: The Four Types and Why Nothing Works Without It
- How Google Reads a Page: From HTML to Index
- SERP Anatomy 2026: What Actually Owns the First Screen
- Zero-Click Reality: What 68% of Searches Without a Click Means
- E-E-A-T Without the Mythology
- Quality Rater Guidelines: What They Actually Say
- Google Core Updates: What They Are, What They Aren’t, What To Do
- Keyword Research From Zero: The Complete Method
- Your First SEO Stack: The 6 Tools That Matter
- Your First SEO Audit in 90 Minutes
How to work through this level
Work through the twelve Level 0 lessons in order, because each one assumes the vocabulary of the one before it. Budget five to seven hours spread across a week, in sessions of about forty-five minutes.
- Days 1 and 2: lessons 1 to 4, the mechanism. Finish by opening Google Search Console and finding one indexed URL and one non-indexed URL on any site you have access to.
- Days 3 and 4: lessons 5 to 9, how Google behaves outward. Finish by sorting ten queries from your own sector by search intent type.
- Days 5 to 7: lessons 10 to 12, the executable part. Finish with the 90-minute audit applied to a real site, not an example.
The checkpoint for moving on is concrete: if you can explain to another person why one specific page does not appear in Google, and point at which of the three stages the problem sits in, Level 0 is done. If you cannot, repeat lessons 2 and 4 before going further.
Level 0 is the first stop on the full path. Once the 90-minute audit is finished, go back to the free SEO course index to carry on with the next level, which builds directly on everything you have just settled here.