If you need to conduct maintenance to your TGB 303RS 125 then it is usually a good plan to have a Workshop Manual to keep just for reference just in case you want to know the right way to strip off a particular component like the Brake Pads and install it again efficiently.
TGB 303RS 125 Workshop Manuals are able to offer certain diagnostic information for your car or truck so if something is not working it helps you work out what the issue is and easy methods to correct it. Then you are able to determine if this can be done yourself or that the job is simply too big it is possible to make a reservation for your 303RS 125 in to a suitable mechanic.
TGB 303RS 125 manual