Click on the dropdown next to your organization's name from the top of the window, and select New Project.
Enter a name for your project in the Project Name field and click Create.
Select the Create Service Account option.
Enter a service name in the Service account name field, and a description for the service in the Service account description field, and click Create.
In the next step, select the role that you want to assign to this service account. In the Role field, select Project > Owner, and click Continue.
If you'd like to assign roles to users and admins, enter the relevant data and click Done.
Click the email address under the Email field. This will be the Service account email address. Make sure that you note this down, as you will need to provide it for the migration.
The value generated in the Unique ID field is the Client ID. Please make note of this value as you will need it for later use during the authorization process.
Now, navigate to the Keys tab, click Add Key, and select the Create New Key option.
Select P12 and click Create.
Once you've created the key, you will notice that a file was downloaded onto your system. Please make sure that you save a copy of this file for later use during the migration.
2. Enabling APIs
We make API calls to Google's servers to request the data on your behalf. But Google does not by default enable all API's, you have to explicitely tell Google which ones you want activated (otherwise Google would make your life easy, right?).
So you enabled the APIs in the step above (not sure why you need to, but some engineer at Google with plenty of free time on their hands decided this was a good thing to do).