How to setup the LinkedIn Ads integration
First, navigate to the campaign where you'd like to connect the LinkedIn Ads integration, then click "Integrations" from the menu on the left side of the screen.
Click on LinkedIn Ads in the list of available integrations.
Then click Connect Account.
You will then be prompted to select the customer account which you would like to connect. Click the radio button next to the appropriate account, then click "Save".
If the account that you would like to connect is under a different LinkedIn 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.