Originally Posted by a mere housewife

There should also be a little 'quote' button just above the compose box (on my screen it's next to the button where you can insert a picture and get a smiley): you can highlight the text you want to quote and click the button and it will put in the formatting for you. If you highlight each quote individually, it will put each quote in a different box. (If you don't see the buttons, I think it would be because of having some compose options turned off in settings?)