Here are steps to add google analytics to your squarespace website.
- Get your Google analytics ID by logging into https://www.google.com/analytics/ and going to Admin->property->Tracking info->Tracking code
- Copy this tracking id.
- Login to your squarespace account from https://login.squarespace.com
- Go to settings
- Click on advanced
- Click on external services
- Enter your google analytics account number-
- Click save