Maybe I'm an idiot, but I'm driving myself nuts trying to figure out how to comment on a just a portion of what someone said on a post. I hit reply and get the entire message, I hit quote and try to highlight and nothing happens? Help please!

You're right, hitting the reply button causes the whole post to be quoted. What folks do is go in to the quote inside the [ quote ] tags and trim out the parts they aren't responding to. If you want to respond to multiple points separately within the message, you can hit the quote button, then copy the whole contents of the message box before typing anything, then paste the whole quote in each time before typing your response. Then you can go in and remove all but the relevant part of the quote above each point that you typed.

The quote button, on the other hand, is a way to quote multiple posts. You can click the quote button on multiple posts within the same thread, then when you click reply, all the posts you quoted will be inserted into the message box.