You have asked a question that needs a careful and exact answer, not easily done in a few sentences. You will need to study it on your own, and then return here when you get confused, don’t understand some detail, or just need some explanation. Just post your doubt/question and members here are ready and willing to help you understand the science of entropy.
Entropy is a measure of the unavailability of a system’s energy to do work.
Spontaneous changes tend to smooth out differences in temperature, density, pressure, and chemical potential that may exist in a system, and entropy is thus a measure of how far this smoothing-out process has progressed.
Take a glass of water with ice in it, the ice will get warmer and the water will get cooler. Entropy is a measure of how far this has progressed.
The relative entropy in this example would be highest after the ice has melted and all the water is at the same temperature.
You can post your question easily. Here it's often called "starting a new thread" or "Opening Post (OP). Just go the the section that best covers your subject, like "General Physics", where we are now. Find the box labeled "Frequently Asked Questions" and then look just below it on the left. You should see a little box with "New Topic". Click on that and then you may enter your question.
May I suggest that you use your word processor to write out your question first? Then, when you're satisfied it is clear and will be understood by all our readers, then "copy" it. Then when you open the "New Topic" just "paste" it in and click "Post".
We look forward to your contributions.