I have been wanting to just check the soundsets out, and have been baffled as to how to get them to install and be usable. Up until yesterday I had no idea how this works. I just happened to read that it is recommended to have a certain version of studio one. I tried that and to my delight, the licenses were installed with 5.2
If you have been looking for a specific way to get each soundset it is pretty much futile. Install 5.2 and then look in the documents folder and you will see a huge list waiting to use. Works well once you knw this.

 

Just copy them all into the Documents\Studio One\Sound Sets. They all have an extension of .soundset

Highlight all the licence files they were created and drag them into Studio One and you're good to go.

 

The point here is that if you have the correct version installed it puts the licenses into that folder for you. Up until I installed this version (from here), there were no licenses to be found. This did it automatically.