It’s just three chords so not hard to bust out during those many times when you’re gathering stones together.
You can use this as the main pattern:
d – d u
In the chorus: Once for each chord in the first two lines. Then four times for each chord on the last line.
In the verse: Twice for each chord.
In the chorus it sounds good if you replace the first down strum with plucking the C-string.
For example for the Bb you pluck the C-string, second fret then strum twice. Because you stay on the F chord for two goes round I like to pick the E-string the second time.
All together it sounds like this: