If you have to perform repairs for your Veli VL90 6 then it is usually a great idea to own a Workshop Manual to use as a reference just in case you want to know the right way to take off a particular part such as the Gearbox and install it again in the correct way.
Veli VL90 6 Workshop Manuals will give you specific diagnostic info for the car so if something is playing up it will help you find out what the issue is and ways to resolve it. After that you can assess if you can do this by yourself or if ever the job is too big it is possible to book your VL90 6 in with a suitable friendly mechanic.
Veli VL90 6 manual