Question On Discord, how is one supposed to reply to an LFG post?

[LegoTekFan486]

Like when someone posts under LFG that they're looking for either a second player, or a team of 4 (or more, depending on the game). How do you reply to that? I've tried just saying "Hi, my screen name is ManicIowa62" and then they don't reciprocate with theirs, so I cannot join them.