Here is a guide regarding how to set up a google analytics account.
It should be noted that this Google Analytics Custom Data Source Provider User Guide PDF contains the same guide, but also how to set it up in the custom data source.
The Set up
Follow the steps below to create a client and get your OAuth client ID and client secret.
Visit https://console.developers.google.com/ and log in with a Google Account that has access to the Google Analytics account you will be extracting data from.
Click Select a Project in the top menu and then click Create a Project…
Fill in the form and click Create.
Type “analytics” in the search box on the Overview page and click Analytics API when is displayed in the results list.
Click Enable API.
Click Go to Credentials after enabling the API.
Click OAuth consent screen.
Type a name in Product name shown to users and click Save.
Click Credentials, click Create credentials and then click OAuth client ID.
Select Other under Application type and type a name for the application.
The client ID and client secret is displayed. You can keep your browser open on this page to easily copy the id and secret to TX DWA.
If you need to find them later, you can review the credentials on the Credentials page