Molly,

Use the Quote Button if you want to reply to their exact post. Otherwise just replying in general, go to the OP (Original Post) and hit reply. Hope this helps hun.

it is easy. Just click on the post, and read it, then hit reply at the bottom of that post. It will show up in the right spot. If you are in flat mode, then they only let you reply at the bottom of the whole thread, and it usually ends up in the wrong place for people reading in tree mode.

I hate flat mode. It is only useful when looking at picture threads.

Of course you can always quote, like ally said.