Analytics Basics in GA4

Google Analytics 4 (GA4) measures what people do on your website as events, groups visits into channels such as Organic Search or Referral, and lets you mark the events that matter as key events. For AI-era marketing, it's where you see which pages attract visitors, where they come from, including AI assistants, and whether they take valuable actions.

In this lesson

• Core GA4 concepts: events, users, sessions
• Channels and where AI traffic shows up
• Key events and why they matter
• Building your first exploration
• Exercise and quiz

What are the core GA4 concepts?

GA4 is event-based: even a page view is an event. That makes it flexible but means you must decide which events matter.

Where does traffic come from?

GA4 assigns each session a source and medium, then groups them into channels using its default channel group. Visits from AI assistants that pass a referrer, such as chatgpt.com or perplexity.ai, typically land in Referral, mixed with other websites. Some AI visits pass no referrer and appear as Direct.

To separate AI visits, you can create a custom channel group with an "AI assistants" channel matching AI domains, placed above Referral. Google's help article includes this as an example. Custom channel groups apply retroactively.

What are key events?

Key events are the actions that represent business value, such as a demo request, sign-up or purchase. In GA4, you mark an existing event as a key event in Admin (Google). Once marked, you can see key events by channel and page, which shows whether traffic is valuable, not just large.

Start with no more than three to five key events. Too many dilute the meaning.

What are explorations?

Explorations, in the Explore section, let you build custom analyses: free-form tables, funnels, paths and more (Google). They're useful when standard reports don't answer your question.

Build a landing-page-by-channel exploration:

1. Open Explore and choose Free form.
2. Add dimensions: Landing page and Session default channel group (or your custom channel group).
3. Add metrics: Sessions and Key events.
4. Drag Landing page to Rows and the channel to Columns.
5. Put Sessions and Key events in Values.
6. Set the date range, for example the last 90 days.

You now see which pages attract which channels, and which convert.

What should you watch out for?

• Sampling and thresholds may apply in some explorations; note any warnings.
• Consent settings can reduce the data you collect.
• Direct traffic often hides untracked sources, including some AI visits.
• Don't compare different date ranges without accounting for seasonality.

How do you connect GA4 to GEO work?

GA4 can't show AI visibility directly, because many people read AI answers without clicking. It can show what happens when they do click. Three useful questions:

1. Which pages do AI assistants send visitors to? These are likely being cited.
2. Do those visitors take key events? This shows the value of AI referrals.
3. Is AI referral traffic growing over time? Compare month over month, using the same channel definition.

Combine these with visibility scans and self-reported attribution for a fuller picture.

Which GA4 reports should you open first?

Start with Reports → Acquisition → Traffic acquisition, with your custom channel group as the primary dimension. Then open Engagement → Landing page filtered to the AI assistants channel. This shows which pages AI assistants send people to and whether those visitors take key events.

A quick example

Illustrative. A B2B software company builds the exploration and finds that its pricing guide gets modest Organic Search traffic but most of the sessions from AI assistants, with a high key event rate. It decides to keep that guide especially accurate and to add a clearer call to action.

GA4 basics checklist

• [ ] Key events defined (3–5)
• [ ] AI assistants channel created above Referral
• [ ] Landing-page-by-channel exploration saved
• [ ] Date ranges noted in reports
• [ ] Consent and Direct traffic limitations understood

Exercise

Build a GA4 exploration: top landing pages by channel; screenshot it.

1. Follow the steps above in your GA4 property (or the Google Analytics demo account).
2. Sort by sessions and look at the top 10 pages.
3. Note which channels drive each page and which pages generate key events.
4. Screenshot it and write two observations.

Quiz

1. What is a key event?

a) An event marked as important to your business b) Any page view c) A Google update Answer: a

1. Where do AI assistant visits usually appear by default?

a) Paid Search b) Referral, or Direct if no referrer is passed c) Email Answer: b

1. How can you separate AI visits?

a) A custom channel group b) Deleting Referral c) A new website Answer: a

1. Where do you build a free-form report?

a) Explore b) Admin only c) Search Console Answer: a

1. How many key events should you start with?

a) 50 b) 3–5 c) None Answer: b

Next: Lesson 6: Prompt research

Sources

• Google, Custom channel groups
• Google, Key events in GA4
• Google, Explorations in GA4