Microsoft Office doesn't install here. ONLYOFFICE opens and saves Office files and looks much like Office. If you picked it in Set up, you already have it.
- Open Discover, the app store: its icon is in the dock. Or open Search (the Windows key), type Discover and tap it. Not there at all? See Add the app store.
- Search for ONLYOFFICE, click it, then Install.
- Now double-click any Word, Excel or PowerPoint file in Files (Windows + E), and it opens in ONLYOFFICE.