This is pretty simple, although drilling holes for the hinges into the surrounding shelf can be tricky with smaller hatches unless you have a right-angle drill. With these hinges, I had to chisel the hatch and counter-sink the hole, in order for the the hatch to fit flush with the shelf. For the fitting the hinge to the hatch, I used my trusty jig saw and a chisel until the hinge fit flush with the rest of the wood.
Check the movement of the hinges, and adjust them if need be. Ideally, the hatch should still be flush with the shelf.
Install a small block opposite the hinges, to keep the hatch from falling into the compartment below.