Heat your threaded insert and press it into place - up to the flange.
Heat a 14mm socket cap screw and screw into place... but not too tight.
The screw should be flush with the back of the steering rack.
Use the short plastic screws or 8mm socket cap screws to secure the axles to the chassis.
Use Loctite or super glue to keep the screws in-place.
Center the steering servo and install the servo horn.
Set screw for the servo horn and one for the steering rack.
Install the front wheels...
Right down to the flange.