Before starting a backup, you need to install the Keepit app in Google Workspace Marketplace. 

1. Sign in to Google Admin page with your Google Admin account credentials.

2. On the Admin Console page, select Apps.

3. Select Google Workspace Marketplace apps.

4. Select Add app to Domain Install list.

5. Enter Keepit backup in the search box to find the Keepit for Google Workspace app and then select on the app.

6. Select the Install button, then follow the install guide.