Let's say you're in a thread several pages long, and as you're reading it you want to quote this post, and then this post, and then this post ... or even posts from another thread entirely.
Just click the +Quote link found in the bottom right of every post, and it will be added to your "Multi-Quote" list of posts. Just keep reading and do this, until you're ready to respond to them all.
If you want to take a post off the list, that you added, just go back to the same area of the post - bottom right - and you'll now see the +Quote turned into -Quote ... hit the -Quote link ... and the post will be taken off of your "Multi-Quote" list. You can play with this, toggle it back and forth, and see the +/- Quote display accordingly.
Okay, now you're ready to respond to them. You might want to respond in the same thread the quote was from, or you might want to respond in a new thread. Either way is fine.
Just go to the message input box of the existing thread or new one ... and click ... "Insert Quotes" ... (see images below) ... and all of the quotes you quoted earlier, will display for you now!
Then just type your response(s) to them and press POST REPLY or CREATE THREAD ...
That's it. If you have more questions, just ask.
Much Love and Peace.