You need that “page” because WordPress needs posts and pages, that is the way it works.
If you do not need it (one page site), you can create a dummy page or duplicate your current one and rename the copy to “page”.
Please, check the videotutorial: https://www.youtube.com/watch?v=sjx7tBv7lco
And the rest of the documentation: https://responsive-muse.com/wordpress-converter-documentation/
It should clarify you how it works.