Study first
Review the ideas behind the questions
These notes explain how GTM containers, tags, triggers, variables, preview mode, and publishing fit together.
Containers, tags, triggers, and variables
A GTM container holds the setup for a website or app. The main parts inside a web container are tags, triggers, and variables.
- A tag is code from an analytics, advertising, or support product.
- A trigger decides when a tag should fire.
- A variable stores or returns a value that tags and triggers can use.
- A clear container setup is easier to test and maintain.
Preview checks before publishing
Preview mode helps you test container changes on your site before they go live.
- Use preview mode before publishing important changes.
- Check whether the right tag fires on the right page or action.
- Do not assume a tag works only because it exists in the container.
- Publishing sends selected container changes live.
Data layer basics
The data layer passes structured information from the site to Tag Manager. This can make tags and triggers more reliable.
- A data layer event can describe something that happened on the page.
- Variables can read values from the data layer.
- Data layer values should match what the tag or trigger needs.
- Good event names make testing and reporting easier later.
Common beginner mistakes
Most beginner GTM mistakes come from publishing too soon or using a trigger that is broader or narrower than intended.
- A tag needs a trigger before it can fire.
- A page view trigger can be used for tags that should run when pages load.
- Built-in click variables can help when creating click triggers.
- Workspaces let you work on changes before they become a published version.