How to set up a YouTube integration
First, navigate to the campaign where you'd like to connect the Youtube integration, then click "Integrations" from the menu on the left side of the screen.
Click on Youtube in the list of available integrations.
Then click Connect New Account.
A window will then pop up prompting you to login to your Google account. Log in with the account that has Owner Permissions to manage the YouTube account that you are trying to connect.
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 Google 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.