With the shape and the image on your artboard, position the shape over and in front of the image. Size everything as desired, and with both selected choose Object > Clipping Mask > Make.
Do you know how to change the shape of the square so it looks more like a plant pot? I want to pull the corners out to make a diangle line.
Choose the Direct Select tool (white arrow), and click the anchor point on a corner you want to move.
You can drag that corner manually, or use the arrow keys to nudge it in any direction. Nudge each top corner out the same number of key-taps:
Thank you so much! Really helpful. I still cannot make it work for some reason though. The fact that I cannot unselect the tool that I'm using isnt helping. I thought if I tapped on the tool again it would release it...?
No, there is always a tool active, and it stays active until you click another. (Arguably, when a dialog is open/active, no tool is active except the OS-level pointer.)