Here's what you can do:
1. Learn the melody: The theme song is mainly based on a single melody line. You can find sheet music online or figure it out by ear.
2. Play it on the lyre: The melody can be played by plucking the strings one at a time, much like a harp.
3. Experiment with strumming: You can try strumming different patterns to create a fuller sound, but remember the theme song is relatively simple.
Since the Mr. Bean theme song is primarily a melody, focus on getting the notes and rhythms right. The lyre is well-suited for playing melodies, so you can create a beautiful rendition without needing a complex chord progression.