Actually, that's not really a dumb question... hehe. That's one key-bind that I never did learn. Instead I learned a different method that I prefer a lot more... try this:
Select the text that you want to find all occurrences of. Press, ALT-F3. This selects all occurrences of that text as a multiple selection. Now you can type whatever you want, or even move the cursor around with the arrow keys if you just need to add/remove a few characters without retyping the whole string - when you have a multiple selection, you have multiple cursors, so moving one cursor moves them all. Oh, and escape will deselect your multi-selection.
After having used this method now for many months, I couldn't live without it. I haven't used the find and replace panel once.