Dubious value, but do as you wish. I'm not sure what additional information you need, since I see you've been to the MPI website already, and the directions are there.
"Before starting a rebuild, you must prepare a repair plan that lists the repairs and states how they will be made. The vehicle must be taken to the inspection station for an initial inspection by the inspection mechanic to ensure the repair plan aligns with the damage to the vehicle. The repair plan must be approved by a qualified inspection mechanic before repairs can proceed. It must include the OEM repair procedures for the make/model/year printed from a published source for all structural repairs. Proper welding techniques must be followed according to the OEM repair guide. The inspection mechanic must ensure the rebuilder has the tools and training to perform the structural repairs. As part of the approval, the station will determine how frequently and at what points during the rebuilding process vehicle inspections will be required."
So to reiterate, if you buy the car, step one is to take it to MPI for the initial inspection where you will show them what you intend to do and that you are capable of doing it to their standard. Once you start work, MPI may (probably will) inspect your work, and your completed repairs must be inspected and approved before being seam-sealed, puttied, or otherwise covered.
The biggest hitch you would encounter, aside from the amount of labour involved in turning a shell to a car that will pass BI, will be finding the reference material for your vehicle if it isn't a North American model.
I don't know what your situation is, but I will say, this is not something you should take on unless you have experience repairing structural damage correctly, and if MPI does allow you to start the process you will not get any chances to cut corners anywhere because your vehicle will remain unregisterable. The equipment required to do this is rare outside of a production shop, but like I said, I know nothing of your situation or skill level, so I can only wish you luck.