This is a ukulele duet accompanied by some clapping, and some soft vocal oohs and hums.
The piece was written with a story in mind, of an explorer who’s explored everything there is to explore on earth, and wants to go to the moon. And he’s building ladders and balloons and spaceships, and keeps trying and trying to get there. I’d try to convey a mood of perseverance, as well as keeping the nice calm of the ukulele.