How to set up the Bing Webmaster Tools integration
First, navigate to the campaign where you'd like to connect the Bing Webmaster Tools integration, then click "Integrations" from the menu on the left side of the screen.
Click on Bing Webmaster Tools in the list of available integrations.
Then click Connect New Account.
A window will pop up asking you to enter your API key for Bing Webmaster Tools.
To obtain your Bing Webmaster Tools API Key:
Access your Bing Webmaster Tools dashboard and select a site.
Click the Settings button (top right corner) and go to the API Access section.
Accept terms (if prompted), then Click on Generate API Key.
Note that if you've already generated a key, it will appear (only one key can be generated at a time).
Once you've obtained your API key, enter it into the field, and click "Save".
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 "Save".
If the account that you would like to connect is under a different API key, click the button that says "+ Connect New Account", enter the appropriate key, and step through these screens again.