All systems go!
Late to reply on this, but I think it’s a bit unfortunate that it requires “connecting” your account rather than simply including a link to your profile on that social media site.
These options should now be a little more robust (when you add your full profile URL it should work too).
It doesn’t All you need to do is enter your username for each site in your profile.
Huh… I was looking in totally the wrong place. I was looking in Preferences rather than Profile. Thanks.