1) Go to Challenges screen and select the 10K Steps Challenge. Tap on "Connect a Device"
2) You will be redirected to the Profile screen, under Accounts tab, tap on "Connect a Fitbit ..."
3) Go through the conversation that follows:
4) Go back to Challenges screen and start a 10K Steps Challenge. Your Fitbit account data will be automatically synced with your Rejuvenan account within the 10K Steps Challenge: