Before following the steps in this guide, please ensure you have a Google Ads manager account and have it linked to your client's account. You can set that up here.
First, navigate to the campaign where you'd like to connect the Google Local Services Ads integration, then click "Integrations" from the menu on the left side of the screen.
Next, either search Google Local Service Ads in the upper right search box, or click the Ads category, then click Google Local Service Ads.
Then click Connect New Account.
A window will pop up asking you to enter your user name and password for your Google Local Services Ads account. Enter the user name and password of the account that has permissions to the Google Local Services Ads client account which you would like to connect.
Next, you will see a screen that says "Application Connection would like to have offline access". Click "Allow".
Finally, you will be prompted to select the customer account which you would like to connect. Click the radio button next to the appropriate account, then click "Connect".
If the account that you would like to connect is under a different Google Local Services Ads account, and you need to enter different credentials to access that account, click the button that says "Connect New Account", then enter the appropriate credentials, and step through these screens again.