Folder Formats: Quick Guide should have all you need, in step-by-step format.
You'll probably want to turn the locks off again. (See #5 in the guide I just linked.)
Sort-of. You're using the Light version of Opus, so the menus and functionality are a simplified subset of the Pro version. Most guides are written for Pro and may contain things that don't apply to Light.
The guide I linked above covers both Light and Pro, making note of where there are differences (e.g. selecting a different menu item, or skipping a part that isn't needed in the Light version).
Shout if you still need help after looking at the guide.