[gm9]

I don't know what the tutorial suggests, not sure I've ever read it, but these are the ground rules for not getting too much confused UIbuilder:

1. Always load eq2ui.xml
2. In the pane on the right select the same module via the tabs as you want to be working in.
3. To that extent, first find MainHUD in the list on the left and press the up arrow icon to the right of the "Up" button. This will move MainHUD right to the top, making UIbuilder open it by default in the right pane. You will be working in this most of the time so that's convenient. Once you save it will be at that position next time you open that UI.
4. When working on windows, it is convenient to press that up arrow icon as well to bring them to the front. I do not recommend moving windows out of the way since that affects their default placement.
5. Some windows are not in MainHUD but in other modules such as Inventory, Journals, Tradeskills, etc. The same as above applies. Bring them to the top for convenience. The tabs on the right pane follow the order on the left pane.