Rover is characterized by four corner assemblies attached to a central frame. Build the corner assembly as follows:

Print the sun, ring, and planet gears first. Then the planet carrier aka output, the gearbox cap, the wheel rim and wheel cap. 

The first step in rover assembly is to install the sun on to the shaft adapter, and then install that on to the motor. You won’t have an opportunity to tighten the shaft adapter after the next step, so make sure it is secure.

Next, use four M4 x 14mm screws to attach the motor to the ring gear. Then grab one suspension arm and a 6817 bearing, and install the bearing over the bearing support on the motor side of the suspension arm.

Once the bearing is installed, carefully feed the wires of the motor through the wire feed hole in the suspension arm, making sure the wires are not jammed and you are able to push the ring gear and motor assembly flat against the support arm. Then install all of the screws to hold the ring gear on to the support arm. Be careful! One of the screw holes only has the motor wires behind it. Do not install a screw in that hole.

Check that the motor can spin freely by spinning the sun gear with your fingers. If the motor rubs or does not rotate, figure out why and fix it before proceeding.

Once the motor and ring gear assembly is secure, install the planets one by one in to the ring gear via the geared slot in the ring gear. After installing each planet, rotate the sun until that planet is 90 degrees off from where it started. Repeat this until the four gears are installed properly.

If the planets are installed correctly, the planet carrier should drop in. Install the carrier with the bottom facing the gears.

Take two 6808 bearings and place them in the gearbox cap. Then screw the cap on to the ring gear.

Next, fit the big rim over the gearbox and on to the large bearing. Rotate the rim while installing it so the spline can mate to the gearbox. Then screw the hub cap on to the rim. One corner assembly is now complete. Do this four times, then attach the corner assembly to the main chassis. Once the corner assemblies are attached to the main chassis, use zip ties to secure the springs to the frame. You should now have a rolling chassis!