The Secret Wedding - Music

My class was just given the task, of learning and playing a piece of music that has been played in a movie, to change that same piece or to compose a piece of music to a small piece of a movie.
I choose to learn how to play a piece of music. This piece is called, "The Secret Wedding" and its the soundtrack of the movie "Braveheart" by James Horner.
So far I'have had two lessons to work on my piece.
On the first lesson, I went through a few tutorials and over a couple of videos of other people playing it.
On the second lesson, I tried learning how to play the begging of the music with the help of a tutorial that I watched on Youtube. However, I had a little bit of difficult doing this, because the video didn't specify the left and right hands and also it was pretty fast.
Towards the end of the lesson I searched for the sheet of the music. However I did not find a free version of it. Therefore I asked my teacher which website was better for me in order to pay online for a copy of the music.

The tutorial that I watched:
https://www.youtube.com/watch?v=KbZyxv0lHy0

Orchestra Video, full song:
https://www.youtube.com/watch?v=C3nwwajqlmQ

Piano Version, Video:
https://www.youtube.com/watch?v=HFFRzug1wfY