Don't know the difference between major and minor? Wanna learn about intervals? Chord construction? Here is the link to the first steps.

http://www.guitartricks.com/lesson.php?input=8078&s_id=78

If you are just starting theory look thru these pages to see if it might answer your questions first. If you need to come back to ask a question feel free to do so.

Theory is one the most confusing things related to guitar. Some musicians avoid it all together. It is highly useful and any aspiring professional should learn as much theory as possible. Good luck on your quest for knowledge!