https pastebin com/UvBy026a
Fix link by adding :/ and .

I didn't see anywhere else that a save file was provided for obtaining this achievement, so for those of you who have already played through the game and don't want to play through the game again; or maybe you just missed a couple notes, here is a save file.

1.) Download the zip.
2.) Extract using 7zip or similar.
3.) Copy the .Sav file to \My Documents\Amnesia\Pig\<PROFILENAME>
4.) Launch the game and load the save file.
5.) The final note can be collected by walking forward and climbing the metal catwalk. The note will be on the catwalk at the top.

Did it work?