GARELLI EUROMOPED 1972 ENGINE RESTORATION

This is the re-assembly of a Garelli Euromoped 1972 50cc Moped. I was asked to re-assemble it , but I did not take it apart originally, so I am working blind as I have never re-assembled one of these engines.
i am not a mechanic and just an enthusiast and hopefully this will be of help.
if anyone is an expert on these I would appreciate you make contact to explain how the petrol gets to the head and whether oil goes in the casings.