Navigating between fields
When you are inside a single-line field (in the right-hand pane or detail pane), you can navigate to the next (lower) field using the Down arrow key on your keyboard, Enter or Ctrl down. You can navigate to a field directly above using the Up arrow key, Shift Enter or Ctrl up.
When you are inside a multi-line field, you can only navigate to other fields using Ctrl Up and Ctrl Down. This is because the up and down arrow keys are alread used to move the cursor to other lines. 'Eenter' is used to create a new line.
It goes without saying that instead of using the arrow keys on your keyboard, you can also simply click inside another field (with your mouse) to set focus to it. After a field receives focus it will accept your keyboard input.