This refers to the very first ball required to move forward in the level.
From the start you'll see a set of golf clubs, pick one and use it to get the ball into the hole in 3 strokes or less.
I managed to complete this by knocking the ball off the tee and then letting it roll down the slight gradient towards the hole. Once it was close enough, I hooked it into the hole, which counted as 2 strokes.