After you have completed the tutorial in Unravel, where you are taught how to use Yarny’s unique yarn abilities, you will come across your very first puzzle, which tasks you with reaching the other side of an empty fountain using water and apples.
The first step is to jump down into the gap, hook Yarny’s yarn onto the water latch to the left, and pull down. This will cause the water to fill the gap, but don’t jump into it, as Yarny can’t swim.
Next, tie a knot between the branches on the floor, creating a slight ramp. There are two spots, one on top of the ledge where you jump up on and one on the bottom a little further up from the pile of apples.
This will create a sort of tightrope that you can then use to push the apples up and throw them in the water, create a bridge to cross. You can check out the picture above to see how it should look once you have completed the puzzle.