First, navigate to the campaign where you'd like to connect the BrightLocal integration, then click "Integrations" from the menu on the left side of the screen.
Click on BrightLocal in the list of available integrations.
Then click Connect Account.
In the window that appears, enter the API Key and API Secret for your BrightLocal account. If you're not sure where to find those credentials, please see here or contact BrightLocal support. Once you've entered your credentials, click "Save".
Next, select the client you want to connect and click "Save".
If the client that you would like to connect is under a different BrightLocal account, you will need to enter different credentials to access that account. To do so, click the button that says "Connect New Account" and follow the above steps.