You're gonna really hate me for this, get the Scott Robertson How To Draw book and also Perspective made easy. Then follow every exercise in the book until something clicks in your head and you can start to make sense of what the hell is going on. Be warned, its an extremely boring and dry book and sometimes very difficult to understand. Also youre going to want to do it in sketchbook for desktop because half of his method is using ellipses.
Good luck, if you get stuck get in touch and Ill try to help