Follow the steps below to remove yourself from a social group:
On the mobile app, navigate to the Friends tab
At the top of the Friends screen tap on the drop down menu under Feed and select Groups
Under Your Groups, select the group you would like to remove
Tap on the 3 dots in the top right corner of the screen, then tap Leave group
Follow the steps below to make your profile private:
On the mobile app, go to Profile > Settings > Privacy and toggle Incognito to ON