My question is what is the difference between simple past and past perfect? Is there any difference of what the two sentences mean? If yes then what is the difference? If not then are simple past and past perfect same ? Actually I want to know when we use simple past and when past perfect?

I don't hand feed. There are plenty of grammar websites going into this in detail - have you looked them up?
If so, just what, specifically, don't you understand about the difference?

Put some of your own effort into learning.