After you have imported the pre-configured tags and triggers file onto your Google Tag Manager, it is important that you update your Google Analytics ID.
To update your Google Analytics ID
Open the Google Tag Manager dashboard.
Click Variables on the side menu.
A list of Built-In Variables appears.
3. Scroll down to locate User-Defined Variables.
4. Click Analytics Id in the list of User-Defined Variables.
The Variable Configuration page opens.
5. Click the Tracking ID.
A field for the Tracking ID appears.
6. Enter your Google Analytics tracking ID.
Your Google Analytics tracking ID starts with UA followed by numerals.
7. Click Save.
Your Google Analytics ID has been updated successfully.