To get to the top of the barn you have to fix the the ladder that has broken down over time. Find the hammer at the back of the old cabin and bring it back to fix the ladder.
The hammer was your tool. You were good with things, and maybe that is why Amelia loved you. You kissed her in that barn not only because you loved her, but because you wanted to say, "I will always put out everything I can to you, to make you happy."