From your dashboard, click on the projects drop down at the top to see a list of all your projects. Note the ID of the project that contains the bucket you want to connect to. Click on that project.
On your dashboard, look for IAM & Admin and click on it.
On the IAM screen, click Add at the top.
In the New members field that comes up, enter: firstname.lastname@example.org
From the Select a role drop down choose Cloud Storage and then Storage Admin. Click Save.
Go back to your dashboard and look for Storage and click on it.
On the Storage browser screen, note the bucket name of the bucket you want to connect to.
Make sure your bucket's settings allow for your images to be viewed publicly.
Finishing up in Blocks Edit
In Blocks Edit, next to your organization at the top, click the integrations icon (). Note: You’ll see the integration option only if you are an admin or owner on the account.
Click the Add button next to Google Cloud Storage.
Enter your bucket name in the Home Bucket field.
Enter your project ID in the Project Id field.
You can override your image permissions with the ACL option, or leave it as is to use your bucket's settings.
If you've setup a Custom Domain for your bucket, enter it here.
Click Save Settings to finish the setup.
Template access settings
You will need to enable your integration for each template that you want to allow using as a source for images in the editor. You can do this in the dashboard by clicking on the preferences icon () on the right side of a template title.
When enabled, the option to set a base directory to access images from is available. For example, if you want to limit access to a certain project folder.
Note: you will need to be an admin or owner on the account to have access to these settings.