Okay, now I can select fields in a single row, but how do I quickly select a field (or fields) in multiple rows?
You can either continue the process of holding down the mouse key while you drag/highlight a region, or use the Shift key (on the keyboard) in combination with the arrow (cursor) keys. I find that the shift key + arrow keys is often more convenient to make sure you select just the rows/columns you want — it is easy to get carried away with the mouse.