My oldest son Christopher moved into his new bedroom several months ago. It's been cramped quarters in there, so over the last couple weekends we built him a new bed and desk, in the process creating much more space.
As you can see the one piece of furniture, the top bunk of a low height bunk bed, dominates the room.
The project was to build a bed into the wall, around the same height as the old bed, and then in the newly opened up space to add a desk. All through the project I had helpers.
One goal of the project was to be done quickly, and to have the furniture be rugged, so we went with 3/4 inch plywood and a painted finish as opposed to the stained finish we usually choose. The meant I could be sloppier on the woodworking aspect, knowing that I could fix things up with putty later. Here is Christopher priming the desk. Note that we are using a white primer. This was a mistake since the final color we picked was a dark red, in which case we should have chosen a gray primer.
The bed installed on one end of the room. Later a ladder and rail were added.
Finally in the cleared space we installed the new desk and storage shelves.