Controls (joystick fire button) Overlay

I'm in the process of creating my gauntlet clone, at the moment I have a single scene called "GauntletGame", not named very well I know, really need to change that some who.

Anyways, all my levels load from the single "GauntletGame" scene by that I mean once the player has hit the exit tile, I go though a Clear Level function that deletes all existing walls, floors, doors etc and unregisters individual events from the World Component, and then call Load Level with a level number, to load the next level.

But the following is what I'm not sure I should do, or how to go about it.

Whats the best way to have an overlay joystick control and fire(s) buttons over the scene so the user can play the game using their tablet, and not a PC which I'm doing now, I've been searching for a good example on this for a little while (I know I will need it eventually), as I've not got into any GUI stuff on unity at this present time, I though I would ask here any advice would be great to point me in the correct direction.

Some videos on the subject would be even better, Unity tutorials have a single example but not with joystick controls overlay just other GUI stuff I believe.

Thanks in advance.

 

The standard assets actually come with a joystick controller, anway here you have a video: