Because they simply cost an incredible amount - print them out! ;)
The parts can all be easily put together with a bit of superglue - what goes where should be pretty obvious.. (or see “instructions” in the file descriptions).
For the rear cover you need four 4x2 mm magnets.
The cover for the front clock hands is not tested.
I used this cheap movement here:
Amazon - I think any movement with these dimensions (56x56x15 mm) should fit.