Before you start the restoration make sure you have the right tools like flywheel puller, clutch holder,Clutch Nut Tool ,Steering head bearing tool to name a few without these tools you'll have a hard time removing things from the engine/bike without damaging them
also make sure to save every little part, even if you dont plan to use them again because sometimes a parts is not available in the market or only bad quality ones are available and due to this you cant progress further with a built !!
also I am glad you choose to restore the bike your self, its fun and you learn alot of new things and actually do a better job than these road side "mechanics".
regarding vespa there is almost everything about it on the internet so make sure to always google first 