To access your "Followers" and "Following" sub tabs you must click your username. Shown here in the red circle.
This is the social overview of your followers, users who you are following and would like to compete with (shown as 'Followed' on the Leader Board).
Following: 'Followed' users are shown on the separate Leader Board and you can compare their score with yours.
Followers: Users who follow you (your username is shown on their Leader Boards).
This section has got 'Following' and 'Followers' sub tabs.
*Please note on the picture above Yousician_User is followed by Yousician_User_2, but does not follow him (marked with the red arrow). Yousician_User can follow back by clicking the icon (should turn green).
The very same way you can 'unfollow' people in the 'Following' tab (switch to another tab and back to update the list).
Find friends: It's fun to compete with your friends! Here you can add people to follow.
Simply type in your friend's username and click the "add" icon so that it turns green. The user will be listed in the 'Following' tab.
PLEASE NOTE: In order to enable other people to follow you toggle the "Show your profile in public searches" option under SETTINGS-->PROFILE: