If you choose to conduct adjustments on your Veli VL125T then it is usually a good idea to have a Workshop Manual to keep just for reference if you need to know the best ways to remove a specific component for instance the Door and match it again in the correct manner.
Veli VL125T Workshop Manuals will give unique diagnostic guidelines with regards to your vehicle therefore if something is faulty it will help you understand what the issue is and tips on how to fix it. After that you can decide if this can be achieved on your own or in case the job is simply too big you can actually book your VL125T right into a nearby mechanic.
Veli VL125T manual