2D hidden object game

Hi there, I’m trying to work out how to do a hidden object game in 2D.

I have just started setting my project up. I have a level, a sprite background, a couple of sprites for object.

I would like to know how to setup to camera, add a simple widget at bottom of the screen and how to basically click on a sprite, make it disappear on click and appear on a widget bar at the bottom of the screen?

Any help or links would be great
Cheers.