music theory can be a bit confusing at first. I found starting small helped me. I read up on how chords where formed and that gave me the base to start understanding how scales were made up.

I found taking it one step at a time really helped. You might find that you struggle with certain bits (or maybe that was just me being slow on the uptake, who knows?) but one day something will just click and you'll be stood there going "ahhhhhhhh!...so THAT'S how it works". Kill Em All's right in that you don't have to fully understand them at first, but it you keep using them it'll all fall into place.

And don't forget, if you found yourself stuck on something, there's tonnes of people on this very forum how have been in exactly the same position and would be glad to help you out.