CocoonJS doesn't currently support Construct2.
As I understand the instructions:
1. Delete the index HTML-file.
2. In that HTML-file, there was a command to create canvas, so this should be now executed from the *js file with a command new Canvas();.
There should be only one *js file and all the java code should be in that one file.
3. There should be no folders, so this means that all the music, *js and *png or *jpg images should be together.
4. Select all files and create a zip.package(*zip) with winzip or winrar.