I hate keyboard trays under my desk. They are too low and it’s just not comfortable to work with. Instead I just screwed an ISBERGET tablet holder backwards against the wall today, and I quite like it. You will need a drill, screwdriver, a screw, a wall plug and an ISBERGET tablet holder.
1. Drill a hole in the top part of the short side of the tablet holder, carefully. I used a regular drill and started with the smallest
2. Drill a hole in the desired spot on your wall. Use a wall plug. (if you have brick and/or concrete walls like I do; if it’s soft material I would skip this step).
3. Screw the tablet holder against the wall firmly. Place keyboard and mouse on top if desired.