Converting Sheet Music to Guitar Tab

I'm trying to use Musescore 4 to convert a piece of guitar sheet music to guitar tab.
I converted the PDF into a Musescore file and opened it in Musescore 4. But I can't figure out how to convert it from conventional sheet music notation to guitar tab. When I select Format/Style and select Tablature the top notes in the sheet music become red but do not convert into tablature. I'm sure I'm missing something easy but I can't figure it out. Any direction would be appreciated.