After you have built the frame, start putting together the X-Axis. It is basically just two assemblies on either side that run on wheels along the longest sides. They are tied together with a single steel shaft which spins. On one end, it is supported on a bearing and the other end it is attached to a motor.
You will need two plastic ends and all sorts of bits, which you will learn to assemble below!
Find the plastic pieces shown here. Be sure to notice that they are assembled as a MIRROR of each other!
The difference is that one side has a larger hole for the motor to poke through.
Find the 8 small wheels, bolts, plastic spacers and nuts. 1/2 of these are for one side, the rest another. The pics show the parts with a metric scale so you can figure out which is which.
Just push the bolt through the plastic, slide on the spacer, wheel and finally, the nut. Make sure it is tight but don't strip it.
Find the four long skinny bolts and longer spacers. Make sure the bolts thread into the motor.
Find the plastic side with the larger hole... it is for the motor. Poke the bolts through the plastic, spacer than into the motor.
No doubt you will want to try out the assembly on the frame...The motor is on the outside...
Find the aluminum adapter thing... it has a hole which is big enough to go over the motor shaft. Align one of the little set-screws with the flat edge of the motor shaft, than tighten it well.
One of the small gears goes flat against the adapter and the long steel shaft goes through the gear and into the adapter.
The other end of the steel shaft has another gear, a spacer and a bearing. Slide the bearing into the other plastic assembly and hold it there with the gear.
Run the two plastic assemblies you have built onto each long side of the frame. Squeeze the gear against the bearing to remove any side to side movement and tighten the set screw.
The other end of the shaft has another gear which pushes against the motor shaft adpater. Squeeze the gear against the adapter and tighten the set screw.
Later you will attach the y-axis to the plastic assemblies and slip the belt on each side over the gear.