This is very simple to print! Every piece (except for the back gate and part of the bottom of the driver's cab) is designed to be printed without any supports.
There is some assembly but it's not hard. To assemble, slot a washer and wheel onto 4 nails, bend and cut the nails, and slot the nails into the slots in the chassis. Then, use the cover plates to trap the nails/axles inside. Assemble with countersunk wood screws in from the bottom (to attach the bottom cover plates to the chassis and also the driver's cab). To join the hopper/dumper to the chassis, and the back gate to the hopper/dumper, thread wire through the holes in the hinges.
(Cut away the “brim/tabs” on the exhaust pipe print; that's just to increase first layer adhesion.)
The author marked this model as their own original creation.