First, navigate to the campaign where you'd like to connect Google Analytics 4, then click Integrations in the left hand menu.

Next, either search Google Analytics 4 in the upper right search box, or click the Analytics category, then click Google Analytics 4.

On the following page, click Connect New Account.

If you've previously connected to GA4 within your account a list of connections will be available to select from.

To connect a completely new account, click the Connect New Account button at the bottom. This launches an authorization window where you will select the account to connect.

On the next page of the popup click Allow. The window will load for a few moments before closing automatically.

The new account will now be authorized and available within the connections list. Select your account, then click Connect in the bottom left to finish the process.