Hey, everybody starts somewhere.
Here's your first tip: do business in the PX, not the regular forums like this guy. If you want to sell, you gotta get 100 quality posts up first, or buy 100 posts to get access to sell. Buying can be done from day one, but caveat emptor!
Second tip: to PM someone, hover your mouse over their username. A small window will appear, and at the bottom center should be an option to "Start a conversation." Hit that, and it'll open a private message window.
Welcome to The Hide, don't be like the OP.