The knowledge stuff from either AOPA or the Mayo Clinic is a review of "good to know" aeromedical factors and risk management items, such as PAVE and IM SAFE. Also counseling on recognizing when you are not safe to fly.
Once you review the online presentation you take the quiz. If you miss too many questions, you are provided the chance to review the information and retake the quiz.
Once you successfully complete the quiz, you are provided the opportunity to enter the required examining physician's name, address, and state license number, then complete the process and print out the Basic Med certificate.
If you do not yet have the completed medical examination, then you can "pause the process", go get the examination done, and return later.
The medical examination is quite similar to a annual physical. The process just asks your doctor to follow the list of things to examine, note that all is well or he discussed any concern with you, and then sign the declarations that he doesn't find anything that would present a major hazard to operate an an aircraft. AOPA has the forms and information plus FAQs to provide to your physician on their Fit To Fly sub-area.
If you regular doc does not want to complete the forms, then seek out the "doc in the box" clinics that routinely provide DOT physicals, and examinations for camp, sports, schools, etc.