Tools you'll need:
Phillips head screwdriver
Threaded screw starter
Marker to mark the hole placement
Hold a mending bracket up, and mark the top and bottom holes. Turn the screw starter clockwise about 10 turns, then carefully remove it counterclockwise. You have now prepped the holes, and the threads will "take" the screws more easily.
I spaced 4 mending brackets along the back, the top hole is in the hutch, and the bottom hole is in the file cabinet. Don't overload the hutch, or it will be top-heavy. If you have small children or pets who could climb onto or knock over furniture, then you'll want to secure the piece to the WALL as well, and you can also place "shims" under the front of the piece at the floor level, to tilt it back slightly. It's just me here, so the brackets will do the job.
Ready for business!