There is a lot of information on riding on this website, as you no doubt have found. You might also check the Team Oregon website for information on riding and the MSF courses they sponsor.
The last part of the Basic Rider Training (BRT) course include the written exam and skills test. If you pass both, you will get a certificate that you can use to get your motorcycle endorsement. You will not need to take any tests at the DMV unless you fail the BRT course.
I suggest holding off buying a motorcycle until after you pass the BRT course.