Shape Notes Plug-In

Brand new to Musescore and had trouble installing a plug-in I really need to use to display shape notes. I downloaded the file "laconic-shape_notes-1e08301". When I open this folder, there are 3 files, a read me, shape_notes.js, and shape_notes.ui. I'm using Mac OS X, 10.7.4 (Lion). When i double clicked shape_notes.ui, it asked what app to install to, I navigated to Musescore, and it tried but said "Can't open file. File extension "ui" not supported.". When I double click the one appended with "js" it opens a text document.

Is this plug-in compatible with Lion? If so, could someone give me step by step guidance on how to install this, I'm sure it's user error as I've not installed many plug-ins before.

Thanks in advance,
-Mel