Adding integrations to popups
When you are creating a popup you will see a Integration menu, you can use it to integrate with other plugins and companies. This is the general help document on this, there are specific help documents detailing how to integrate with the specific thing you may want.
When you click on Add Integration, there are a number of options and you can add as many integrations as you want.
When you have all the integrations you want, you can close it (top-right corner) then save / publish.