Please help me , can someone explain to me what does percentile mean ??? How it's different from (overall correct) ? How can I evaluate my performance from percentile if it's 25th or 75th ?

percentile is where you stand compared to others, for example if you are on 75 percentile it means you did better than 75% and worse than the top 25%.
Here's some explanation in simple english:
https://simple.wikipedia.org/wiki/Percentile