If you need to perform fixes on your Honda CRF150R then it is usually a good idea to own a Workshop Manual for personal reference in case that you want to know how to take off a specific component much like the Brake Pads and fit it again in the correct way.
Honda CRF150R Workshop Manuals offers you distinct diagnostic wisdom for the car so if something is faulty it will help you ascertain what the problem is and tips to repair it. You can then determine if this can be achieved yourself or that the job is too big you could book your CRF150R in to a suitable repair garage.
Honda CRF150R manual