Help with a basic touch movement system.

I’d like to have a movement system for my mobile game where the player can touch anywhere on the screen and have the actor mimic the movements. For example, if a player moves his finger up down left or right anywhere on the screen the actor will too. This is so the player’s finger won’t cover up the actor as my game requires precise movements. A perfect example of what I want is here. If someone could walk me through it or point me towards a good tutorial that would be really great. I feel like it shouldn’t really be that difficult.