To quote someone's message in your post, you use "reply" at the bottom right of their message. This inserts their post in yours as a quote. Hit the return key before typing, ensuring the cursor is on the line after the quote, so you post outside the quote, rather than in it.
If you have some text you want to quote from elsewhere. Click on the "quote" marks at the top of the message box and paste the text into the quote box that appears. To get out of a quote box and type normally again, just hit the return key to start a new line again.
If you have some text you want to quote from elsewhere. Click on the "quote" marks at the top of the message box and paste the text into the quote box that appears. To get out of a quote box and type normally again, just hit the return key to start a new line again.