Permanent Welcome Page?

I recently acquired admin to an older page – https://www.tanyatucker.com. I’m attempting to make a “coming soon” page only and have downloaded a plugin. The plugin “works”, but the old welcome page is still active and is the first thing you see. I’ve gone through all the plugins, themes, settings, pages, and I can’t find where this page is being activated.

Does anyone have a suggestion?