Use your right hand. The small gold numbers are your fingers: 1 = thumb, up to 5 = pinky.
Find the group of three black keys nearest the middle of your piano. G is the white key sitting between the first two of them.
B♭ is a black key — the last one in that same group of three. It's the only black key in this whole song.
Every pattern rises up (1‑2‑3‑5) and falls back down (3‑2) over the same keys. Up the hill, down the hill. That's the whole song.