Dial a favorite
This page is for devices with calls and mobile data.
Open Phone > Favorites > tap the favorite. The call goes out to the number shown under the name, which is the contact's primary number.
To use another number, tap the arrow at the right of the row > tap the number.
You first need to make the contact a favorite (learn how).
Checked against the LuneOS code and installed apps. Nobody has tried these steps by hand yet, so tell us if something differs.