Assembling the mount is pretty simple. You will need:
+ 2x - 3" to 5" long bolts/screws
+ 1x - 2" long bolt/screw
+ 1x - package of small washers
+ 1x mending plate
+ 8x - nuts (may come with the screws/bolts you buy)
+ 1x - bolt/screw cap (optional)
and some pliers and a screw diver
All nuts and bolts should be 1/4" in diameter with a thread count of 20. 20 thread count is also called "course" on some packaging. This is the diameter and thread count used for tripod screws and, while only one of the screws will actually be functioning as a tripod screw, 1/4" 20 thread screws are easy to find and it makes it easier to only have one standard for all the screws/bolts and washers/nuts.
For the mending plate, many sizes should work as long as you can get the 1/4" screws/bolts through the holes and there are enough holes to give you flexibility in where to place the camera. The one we use here is 3" long and has 4 holes.
Step 1: Step 1: First bolt and mounting plate
We will be using nuts on either side of the mending plate to secure the screw's position so think of this first nut as half of a clamp that we're building around the stable base of the mending plate.