You're nearly there, nice work! 😎
In order to allow your Google Cloud project to interact and communicate with your Google Search Console.account, you'll need to perform 2 simple steps.
Click on the top left burger menu and head over to APIs & Services > Credentials.
Locate your Service Account (previously created in this step) and copy the email address:
In order to add your Service Account email in the Google Search Console you'll need to find the Settings page. On your domain instance, scroll down the left sidebar until finding the "Settings" page.
We're going to add a new user to allow Google Cloud to perform task on behalf of your Google Search Console instance. To add a new user, follow these steps:
Click on "Users & permissions" (second setting choice),
Then click on the "ADD USER" blue button.
Upon clicking on the "ADD USER" button, you should see a new pop-up prompting you to add the following information:
Email address: That's where you'll paste your Service Account email,
Permission: Select "Owner" to grant full access to your Google Search Console account.
Note: You'll always be able to remove this user if needed. This user will mainly be used to grant FlashSERP the authority to index content on your behalf.
You're good to go, good job!!! ⚡
If you want to know how to add your first sitemap.xml to FlashSERP and start populating your URL Manager, head over to this tutorial.