first, you have to start a session
then, you have to open the xmb and select your friend
then, you hit triangle to send an invite message
then, your friend has to open his xmb
then, he has to select your name and hit triangle, read the message, and accept the invite
none of this is explained in the manual, i had to google search for it and dig through a message board thread somewhere, which was filled with misinformation because no one on there understood exactly how to do it, either
the process is a special kind of distinguished mentally-challenged
dare i say, a methodis kind of distinguished mentally-challenged