If you wish to undertake fixes to your UM Matrix II 170 then it will always be a good plan to have access to a Workshop Manual to keep just for reference in case that you want to know how to remove a certain component including Wheel and fit it again appropriately.
UM Matrix II 170 Workshop Manuals will give you targeted diagnostic info for your car therefore if something is broken it helps you identify what the issue is and how to repair it. You can then assess if this can be achieved by yourself or in case the job is just too big you can actually book your Matrix II 170 in with a decent garage.
UM Matrix II 170 manual