If you need to undertake maintenance tasks on your Vespa GT 200 then it is usually recommended to have a Workshop Manual to use as a reference in the event that you need to know proven methods to remove a certain part for example the Brake Discs and fit it again accordingly.
Vespa GT 200 Workshop Manuals gives you unique diagnostic guides for the car therefore if something is playing up it can help you figure out what the issue is and the best way to fix it. After that you can decide if this can be achieved on your own or that the job is just too big you could make a booking for your GT 200 in to a local mechanic.
Vespa GT 200 manual