How to play this song ?

These are single notes, not chords.
Each note must be played individually.

There are different notations, like, A B C , DO RE MI , Sa Re Ga and numeric notation 1 2 3.
Choose one that fits better for you.

You can distinguish the octave by the color of the note and if it is UPPERCASE (high pitch) or lowercase (low pitch). Enjoy

Little Do You Know

Alex & Sierra Pop

"Little Do You Know" by Alex & Sierra is written in the key of C major. It is a heartfelt ballad that tells the story of unrequited love and the pain of keeping one's feelings hidden. The song was performed by Alex Kinsey and Sierra Deaton, who won the third and final season of the American version of "The X Factor" in 2013. Alex & Sierra also co-wrote the song along with Toby Gad. Known for its emotional lyrics and haunting melody, "Little Do You Know" became a popular hit, resonating with audiences worldwide.