First, navigate to the campaign where you'd like to connect the Basis Platform integration, then click "Integrations" from the menu on the left side of the screen.

Next, either search Basis Platform in the upper right search box, or click the Ads category, then click Basis Platform.

Then click Connect New Account.

If you haven't already done so, you'll be asked to enter your Username and Password for your Basis Platform account.

You'll then be shown all available Basis Platform accounts linked to the credentials you've entered. Choose the exact account you'd like to integrate, then click Connect.

Your client's Basis Platform account will then be connected to the dashboard.