I cannot see the chocks and the tiedowns in the walkaround, or the walkaround view are messed up

This is usually caused by incorrect installation or by using an incompatible mod done to your aircraft.

Be sure to:

Remove both the REP aircraft and the original aircraft folders from X-Plane “Aircrafts” folder
Reinstall the aircraft either using the original zip from the store (if Carenado) or X-Plane installer (if default Laminar aircraft)
Install REP as per manual instructions, making a copy of the original aircraft folder