1) Click on another tab so the current tab can remain open.
2) Find your text.
3) Hold the left mouse button down while selecting your body of text. (it should change colors, generally blue while you are scrolling to encompass the part you want.) Sometimes you have to simultaneously scroll left or right to get all that you want.
4) Once you are done, right click the shaded area and select "copy" from the popup menu.
5) Click back on your tab and place your cursor where you would like your text to go. The cursor should be blinking.
6) Right click at the blinking cursor and select "paste" from the drop down menu.
This next step can be done two ways:
7) You can click the "quote" icon located on the tool bar (1st icon from your right), place your pointer between the two BB codes where the blinking cursor is at.