I must be retarded

I just took the adv_preloader tutorial here on kirupa, and I got it to work just fine using their methods. Here is my question, I would like to have my dynamic box move along with my preloader bar…using their method of loading frames wise it works but I tried to figure out how to to do when loading bytes instead of frames and well I have failed. I would appreciate it if someone could take the time out and answer probably an easy question thanx