I don't want to sound like a know-it-all, but allow me to answer those questions.
Question 1:
I could try to explain it here, but I think your question would best be answered over in the Emulation section of PC. To be honest, I do believe that question has probably been asked before, so just use the search function. ;D
Question 2:
PM stands for Private Message. A Private Message is like an Email but ran directly through the forum. If someone wants you to PM them, simply click on their name, scroll down the little box that appears underneath, and select the option "Send Private Message to <insert name>."
Welcome to the forums, Suthi. We're always glad to have another member amongst us!
I hope you have a wonderful stay here at the Pokecommunity. It's a very friendly atmosphere just full of interesting content. I'm sure you will have all kinds of fun.
Take care now.