Click the
+quote button on all of the posts that you want to quote. A message will pop up saying that the post has been added to your multi-quote queue.
When you're ready to add in all of the quotes to form your post, in the text box click on "Insert Quotes"
A Review Selected Messages pop up will then appear. You will then be able to review the posts you are quoting, and you can remove any quotes and rearrange the order of the quotes if you so wish.
When you've finished reviewing your quotes, just click on 'Quote Messages' and the Review Selected Messages pop up will go away and your quotes will be added to your text box.
If you want to quote one post but address multiple parts of it by breaking the post up, just put space between the text that you want to quote, highlight the text, click on the three dots in the text box (next to the smile face), and click quote.
This will put tags around that text for you.