I can't find explanations about "achievements"

Sometimes I receive a message telling me that I have a new award, like Pack Leader or Quick Knockout. What does this means actually? Where is this stuff explained?

 Try Home>Awards>Achievements and then click on whatever you received.

Hmmm, I thought I did it, and nothing happened, but I will try again.

I clicked it, yes, it works, I think I first tried to double click it! Yes, funny, but not really interesting. I saw that I didn't checkmate still with bishop, and that I won without losing any piece, okay

I think it is chess.com giving to you after you achieved something, like a certain number of comments, etc.

Maybe there's an achievement for learning what achievements are.