Step one: put together the bare bones of the printer. The plastic parts were all printed from https://github.com/jcrocholl/rostock. I modified the BOM heavily and will post when it is closer to completion and not a total mess. The only missing info was dimensions for the top and bottom plate. Courtesy of a google search:

A few missing dimensions were hole diameters and the location of 6 bolt holes. I used a 7/64 bit, but the hole diameter is not critical. The missing holes (red Xes) are easy to mark by lining up the motor_end with the 2 existing holes.

Overall it was a straightforward assembly. There are some small issues I will have to fix later but are not crucial to operation. One of which is that the combined height of the endstop holders, bottom plate, and motor_end is FAR longer than a standard M3 screw. Countersinking the motor_end or bottom plate later on will fix that.

The carriage and rod assembly takes a little bit of effort, since each side gets two bolts that face each other.

Linear bearings were attached to the idler ends with zip ties. It is not my favorite method of assembly but it does hold pretty well. (Ignore the wires and belt for now)

The final product looks something like this and moves smoothly with very little slop, which was my biggest concern with this step.