I started with 5 pieces of foam core. I printed out the words to the song and mounted them on the boards, framed in the corresponding colors: black, red, white, green and yellow. Then I cut out hearts in each of the five colors, and attached Velcro to each heart, as well as each board.
When we sing the song, I remove all the hearts, and then add each heart back to the board as we sing the corresponding phrase. Without the boards, you can simply hold up each colored heart as you sing the song, but the board visual is great to have up in the classroom for you and your kiddos to refer to as you teach these lessons!