Help PLZ

Hello.

Erm this will be the most n00b question any of you guys will hear EVER.

Ive got an image on the bottom layer. I want to put a square over it with a circle on top of that which shows a certain part of the image below.

Thanks for help.

Create a new layer. Draw your square. Create another layer, draw your circle. Place circle over part of image you want. Command/Alt click circle layer. With circle selection made, go to picture layer and copy and paste. Move new pasted layer up to the top.