If you want to do maintenance to your Yamaha X City then it is usually recommended to have a Workshop Manual to keep just for a guide if you need to know techniques to strip off a specific part for instance the Exhaust and fit it again appropriately.
Yamaha X City Workshop Manuals can offer you unique diagnostic guidelines on your automobile so if something is broken it helps you figure out what the problem is and the way to fix it. After that you can assess if this can be done yourself or if the job is just too big you could book your X City in to a nearby car garage.
Yamaha X City manual