A "putback" is a rebound/shot combination by the same player. To activate event assist support for this action, go to the "More" tab and select "Event Assistant". On that screen the first listed feature is "Putback Fieldgoal". Turn this option "ON".
The way this works is that if the app detects a shot by the same team as the previously missed shot with no rebound between it will present the UI to insert a rebound for the second shot by the same player. So the sequence of events would be shot missed, shot made/missed - tap the offensive rebound button which has the player showing. The app will insert a rebound before the current shot.
So 3 taps (select player, touch court for shot, touch rebound button) are needed for a putback.
The way this works is that if you add an offensive rebound with the feature enabled it will present a floating button over the basket area of the court with the same player as the rebound and the shot indicator as prompts. Touching this area will add a shot for the indicated player. After selection you can move the shot to any location on the court and edit the made/miss status as will other shots.
So 3 taps (select player, touch court for offensive rebound, touch floating player + shot button) are needed for a putback.