The first thing the user does is choose where to get the information to search from.
The first thing the shortcut does is figure out if a song is currently playing or paused on the phone. If so, it gives the user the option to select it.
If that's what the user chooses, it uses that information plus the word "karaoke" to search.
If the user selects "Pick for me", the shortcut chooses a random song from the phone's music library and uses that information plus the word "karaoke" to search.
Or the user can input the artist and title using the keyboard.
Then the shortcut passes along the search terms to the Youtube app if it's installed or Safari if Youtube isn't installed.