If you choose to do fixes on your Veli VL125T 8 then it is usually recommended to own a Workshop Manual to keep just for personal reference in case you need to know the right way to strip off a particular part such as the Clutch and match it again in the correct manner.
Veli VL125T 8 Workshop Manuals will give specified diagnostic facts on your automobile so if something is broken it helps you discover what the issue is and some ways to correct it. You can then evaluate if you can do this yourself or if the job is just too big you could make a booking for your VL125T 8 into a decent garage.
Veli VL125T 8 manual