Neo Scooter Yamaha Neo's 50cc Ignition Key Cyclinder.?

Yamaha Neo's 50cc ignition key cyclinder.? - neo scooter

I carry the keys to the bike on a name and thought of buying the ignition key cylinder and fix it myself. But I do not know how to do it, but he was a mechanic who was not too hard to tell. (Note, however, that in this model is also the seat lock)
Someone can do a detailed step by step?
Thank you.