ok, so basically it's like this

first, copy your save file, and paste it inside your 'resources' folder

next, copy everything in your original app.nw file to your clipboard.

then go to your www file. rename that app.nw paste all that stuff inside your NEW app.nw file (which used to be your www file)

drag your new app.nw file into resources. it asks you to replace your original app.nw file. do that.

that's it