Get an easy book which does a lot like Liboff or Basdevant to go along with the YT lectures. It helps to read something, too. Or the 3rd volume of Feynman's lectures.
I've watched ( I'm watching) susskinds lectures on iTunes and I'm reading the Feynman lectures and you need calculus for those two. So if you arent familiar with calculus, learn calculus. Or , read " The Quantum Universe: Everything that can happen does happen " by Brian Cox and Jeff Forshaw. Its less intensive mathematically.