In the card game My Soundtrack, players have a hand of Song Cards, each of which displays a QR code. The QR code redirects to a website endpoint and encodes a song title and artist. The website endpoint takes the song title and artist and passes those parameters to the Spotify API, receiving a song preview URL in return. The website then redirects the user to the returned song preview url (if available).
To model that functionality here, I've created a simple form for users to input song title and artist. This is the information that is encoded in the QR codes on the Song cards.