Welcome aboard, Frondly
! When you see a "Post" box, above the one you typed, then that is a "Reply". To respond to a message (like I'm responding to yours now), just scroll to the box at the bottom of the screen & type a Reply then click the "Post Quick Reply" Button below it.
I just learned to use chat, myself, about 4 weeks ago. In the dark-blue (shaded) line near the top of the screen, there are titles in white letters. Chat is one of them. Just position your mouse on the word "chat" & click. There will be a long box at the bottom where you can type messages.
Btw, the chat is a little weird. If you try to send a message & it wont pop up on the screen, you've been accidentally bumped out of chat (software bug, I think). If it does that, just wait & it will ask you to log into chat again.... very strange.
Anyway, it's a very friendly & info-packed site! If ya have more questions about using the forum, just ask!