If you wish to carry out fixes on your own TGB 303RS 125 then it is always a good plan to have access to a Workshop Manual for a guide in the event that you need to know tips to remove a certain component for example the Brake Pads and match it again adequately.
TGB 303RS 125 Workshop Manuals will give identifiable diagnostic guides with regards to your car therefore if something is not working it will help you understand what the issue is and how to correct it. You will be able to analyse if you can do this yourself or if ever the job is just too big you are able to make a reservation for your 303RS 125 in to a trusted repair garage.
TGB 303RS 125 manual