After navigating the the Account Management screen under Settings -> Account Management, select the Google (Drive/YouTube) tab. If you're accessing the system remotely, you'll immediately see the following notice:

Due to API limitations that Google imposes, when you add an account, you must have desktop GUI access to the machine when you add an account. However, you can enter the account provider settings from your remote machine before you do this.

Create a Client ID for CaptureCast

1. Log into the Google Cloud Console with your Google account. It doesn't matter what Google account you use. (It need not be the same account as the Google Drive or YouTube you want to access).
2. Select a project or create a new project. In this case, I've selected the "Latest Google Test" project.
   
3. Go into your dashboard, then find and click Explore and enable APIs.
4. Click Enable APIs and Services
   
5. Search for and enable the Google Drive API, then also the YouTube Data API.
   
   
6. Click "Credentials" in the left-side panel, then Configure Consent Screen.
   
7. Unless you are planning to use an account outside your organization, select Internal, and click Create. This will restrict usage to users within your organization. If you do not have a gsuite account, you may not see the Internal option, and in that case, External will work fine.
   
8. Enter the information into the fields with asterisks next to them, you can enter whatever values for these fields that you'd like. After you save this information, you can return to the Credentials page using the left panel.
9. Click on the "+ CREATE CREDENTIALS" button at the top of the screen, then select "OAuth client ID".
   
10. Choose an application type of "Desktop app" and click "Create". (the default name is fine)
    
11. It will show you a client ID and client secret. Copy these somewhere temporarily, until we finish up here, then we can put them into CaptureCast.
    
    
12. (If you selected "External" at Step 7 continue to "Publish App" in the Steps 13 and 14. If you chose "Internal" you don't need to publish and can skip straight to Step 15.)
13. Go to "Oauth consent screen" and press "Publish App"
14. Click "OAuth consent screen", then click "PUBLISH APP" button and confirm, or add your account under "Test users".
15. Enter the noted client ID and client secret into CaptureCast, then click Save.
    

Adding a Google Account

As previously mentioned, in order to add a google account, we'll need to have graphical user interface access to the unit itself. This means that you need to have connected a monitor, keyboard, and mouse, or be using a KVM, or have devised another method of remotely accessing the operating system GUI.

Once you're on the local machine, however, the process is straightforward. Simply click Add Account, and a Firefox window will open with a Google login prompt. Log in to google as you normally would, selecting the account or brand account you'd like to use if you have multiple tied to a single login.

Finally, click Allow when prompted to give access to Google Drive and YouTube

Once Firefox loads a blank page - you're done. Simply close the Firefox window, and back in CaptureCast, you should see that you've successfully added a new Google Account.