If you require full mouse functionality without having an actual mouse, then you can use the Virtual Mouse function by holding L1 and pressing R3. By doing this, the R3 stick becomes your movement for the cursor, whilst L2 and R2 as left and right click respectively.

Personally I hardly use the above unless I am messing around with my HUD or hovering over things that don't show otherwise. Just clicking the touch pad should navigate you through certain windows. It's a big change going from keyboard and mouse to controller but eventually you'll find a way that works for you if you decide to stick to it.