1. Enable the BigQuery API
Go to Google Cloud Platform Web Console. Once you are on the home page of GCP's Web Console, head to the navigation bar on the left-hand side of the screen. Once you open the Navigation bar, head to the APIs & Services tab, and select Library from the resulting drop-down.
This will take you to a page where you should input “BigQuery API” in the search box. Once it pops up, go ahead and click on it.
Now, click the Enable button to enable the BigQuery API.
2. Authenticating with a service account
Now let’s create a service account. Use the navigation bar on the left-hand side again to navigate to the APIs & Services tab and select Credentials from the resulting drop-down menu.
Once you are on the Credentials page, click the Create Credentials button at the top of the page, which will trigger a drop-down menu. From that drop-down menu, go ahead and select Service Account.
Under the Service account details, title the account target-bigquery and click the Create and continue button.
Now, let’s grant this service account access to the project by adding two roles.
The first role should allow the service account to be a BigQuery Data Editor. This allows the tap to edit the contents of the data sets (write permissions). Make sure that the second role is BigQuery Job User. This is a bit self-explanatory, it allows the target to run jobs. After adding the two roles, hit the Done button.
Now, using the navigation panel again, head back to the APIs & Services tab and go to the Credentials tab within the tab. You should see the service account you just created near the bottom of your screen. Go on and click on it.
Select the Keys tab
Click the Add Key button which will prompt a drop-down. Once it does this, click Create new key.
Finally, select JSON for your private key and click Create and save it.
Make sure you keep this somewhere safe. This file holds the credentials that you should use to connect your BigQuery account to Optiply.
After this, all that is left is to connect Bigquery to Optiply. For that Follow the path on the video below.
That's it! You are all set.