Like those.

Sheet music in front of me with my notes circled in respective colors. For example, my F# bell would be blue. So when a blue note would be coming up I knew I needed to get my F# bell ready and ring it when the time comes.

If you removed the colors I couldn't begin to play. Well, I could figure it out because I know some basic music theory now. But I'd definitely want to color them after I figured out which bell was which.

The way I played handbells was equivalent to like a dozen people sitting at a piano and each getting only a handful of keys to play when they come up. If I only had to worry about hitting 4 or 5 piano keys when they came up in a piano song I could do it lol wouldn't say I could play piano though.