Start by copying your Google Analytics 4 Tag. Here is information on where to find that: Where do I find my Google Analytics 4 tag?
Next, go to Manage --> Business Settings --> Integrations
Scroll down to the Google Analytics 4 integration and click the Enable button, then paste your GA4 tag into the box and click Enable Integration.
To utilize the integration, you will need to have at least 1 booking. You can create a test booking by clicking the Create New button in the upper right corner of your Check Cherry account.
For more information on setting up and using Google Analytics, see their support site linked below: