Hi Butvoh and welcome to LQ.
I recommend that you edit your original question to or post a follow-up to provide a bit more information to persons who may be able to offer you some assistance.
You should cite any links or references to books which you have already read on this subject. You should indicate if your interest is focused on a particular area of RHEL. You should indicate if your interests are purely academic, or if you are considering certification.
Knowing these answers will help others to help you effectively. If you just ask your question in the initial, open-ended form, then people will be unable to determine what your interests are, and also what information you have already referenced prior to your question here.
If you have any questions about LQ and how best to benefit from the site, please review the following links:
Welcome to LQ - provides you some guidelines regarding how to post effective questions and welcomes you to LQ
Project Tools FAQ - also provides you some guidelines regarding how to post effective questions
I'll also note that if the intentions of your questions are purely certification centered, then it may make sense to move your thread to the
Linux - Certification forum. Depending on your answer, I can move the thread for you, or you can click on Report to request your thread be moved.