This is my 3rd day with Dorico.
I want nothing on the page but the title before I import the whole prelude all done by Brand X software. How do I get rid of the empty staff?
…actually want to lose both staves…
Just import the new music. It should end up in a separate (second) flow. Then you can delete the original, undesired flow.
Looking at your layouts in the panel on the right, if you want to control which movements appear in separate layouts, take a look at this introduction to how players, flows, and layouts relate to each other (and how you can assign/un-assign them from each other).
If you want a title page before any music appears, information relating to master pages might be helpful to you as well.
You have created two flows, “prelude” and “fugue”, which presumably don’t contain any music yet, but they do have the Guitar player assigned to them.
So, you get a placeholder of a quarter note rest for each flow, and that is the only thing in your score so far.
If you were going to write the music in Dorico instead of importing it, you would just overwrite that rest with the first note that you enter.
When you import the music, it will import into new flows, so setting up those two flows and changing the titles was actually a waste of time, with the benefit of hindsight.
As a general principle, if you are importing music from somewhere else, import it first and then sort out the flows and layouts when you can see what you have, and what needs to go where.
If you try to do something in setup mode that will permanently delete some music, you will get a warning dialog to confirm you really want to do that.