If you wish to conduct maintenance tasks on your Sym GTS 200 then it will always be a good plan to have access to a Workshop Manual for personal reference just in case you need to know how to remove a particular component for example Brake Discs and match it again appropriately.
Sym GTS 200 Workshop Manuals can offer you specified diagnostic information for the vehicle so if something is broken it will help you figure out what the situation is and ways to correct it. After that you can analyse if you can do this on your own or that the job is too big it is possible to book your GTS 200 right into a decent car garage.
Sym GTS 200 manual