Only certain apps can be linked for fitness week, we are testing this feature and may invite more apps to participate in the future.
Crazy Kung Fu
Groove Fit Kingdom
Each developer has integrated the SDK differently.
When you enter the app look for instructions on how to get the code, then enter it on Sidequest to link the app to your Sidequest profile and earn achievements for completing mile stones.
On your public profile scroll to achievements to see which apps you have connected.