If you dontknow the CAGED system yet start there! And after that go to 7 or more positions.
The use of these positions is that you will know to play the scales anywhere on the neck. As well that you will learn to play the 7 modes at the same time.
Learn one thing at a time if you want to know the circle of fiths first try to remember the circle. Write them several 100s times down. Than play thru it, e.g. C,G,D,A,E etc do that in Major first.
I hope these answers will help you, feel free to ask if its not clear. I'm sure there are more people who can tell you the benefits of these positions.
Grtz Ray