FOr installing on OSX:
1. you have to first run the pkg, this will create a folder called "gravity_waaaves_DSKv1_19" in applications (or wherever else you choose to install) and install "gravity_waaaves_DSKv1_19.app" inside of that folder.  
2. copy the enclosed "data" folder alongside the .app inside the "gravity_waaaves_DSKv1_19" folder
3. if you've already got a registered copy of GWDSK somewheres on this same computer, just copy the reg.json file over the existing reg.json file inside the data folder you just copied.

and actually read the other readme next to this file too!