Step1: Sign in to your Google Tag Manager account.
NOTE: If you do not have Google Tag manager account, you may find below link helpful:
https://support.google.com/tagmanager/answer/6103696?hl=en
Step 2: Go to Marketing -> Website Settings -> General Settings ->Site Management tab-> Google Tracking and Analytics card and paste Container ID in Tag Management ID box.
Step 3: Click on Save.
