This is an example of implementing a tag/trigger on GTM. We are going to start with Google Analytics
Typically I would install Analytics tag via Google Sitekick.
This serves as an example of how I would implement Google Analytics without any plugins etc
- Click Add New Tag

2. Select Google Analytics as Tag -> Tracking Pageviews (basic) -> Input the Google Tracking ID -> Save this as a variable so you can use this again later.

3. Once you have saved the Tag, you have to add a Trigger. What will trigger the GTM GA tag to fire to GA?

4. Debug – Debug for GA tag, see if the GA tag is fired for pageviews.