You can start from the finished official Model A.
Some M-motor can be changed into L motor and servo motor.
Waiting for Inventory to load
Building Instructions For Sale
This is a Premium MOC, and the instructions to build it are being sold by the designer (shengcarl)
You will receive building instructions of type 3D File - LEGO Digital Designer LXF from the designer once you have organised payment with them.
Use LEGO Digital Designer to open these files and generate step by step building instructions.