Find a course sequence that you think is important to know from a university website. You can find these on (under)graduate requirements pages. Download the syl

Find a course sequence that you think is important to know from a university website. You can find these on (under)graduate requirements pages. Download the syllabi in order and do the hws/projects/tests. Try to stay on some regular timeline. Use the course calendar and set goals according to it. Check your work and grade yourself. You can prefer to choose courses/schools with their materials online and that use books/solutions freely available online too. Since you say you already chose books, find a course with the appropriate prereqs that uses them, otherwise you may have chosen the wrong book. Many reputable programs have professors that post everything online. When a link is broken you can supplement by buying the material on coursehero or the like. A motivator is to think of some people who have some education you don't, and you want to be like them. They followed these syllabi like orders in the past, so so should you. I take the procrastinating on youtube to mean you are intimidated. Maybe from analysis paralysis. So having a schedule to follow for some self assignments that you will grade will be a motivator I think.