I'm not sure what kind of blocks you mean, but it sounds as though the pole was actually sitting inside the blocks? Always
place the pole on top of blocks so it can easily fall away if your horse knocks the rail. I don't recommend teaching yourself or your horse how to jump, but, if you can't get a trainer and you absolitely insist on teaching yourself to jump, I'd strongly recommend some beginner jumping books to help you out. Just remember to READ first!! And please, please, please don't practice jumping without having an adult there, just in case.