Joe, I build a murphy bed using the hardware kit from Rockler. Mine was queen size and vertical. It is (in my world) a complicated project and the instructions took several readings before it started making sense. It is also a very large project and much of the assembly for mine had to be done in the bedroom as completed components would not have made the turn to get in the door. Just like Daniel said, go slow and read carefully. After marking out items, especially mounting holes, etc. sit back and look at them carefully to make sure they make sense and look right.
Good luck!!! Rob