When you've downloaded the most recent release you have to do a few things to get it up and running.
First, you have to make sure NodeJS is installed. If not, it can be downloaded here.
Second, you need to install the dependencies. This can easily be done by running the next command in the root folder of the project.
npm install
After this, you have to get the required keys from Spotify and store them in the 'config.json' file. You can get the keys here.
Now, you're all set and can start the application by running the next command in the project root.
npm start
For the customization options you can consult the customization page in the wiki.
Spotify Wallpaper is licensed a MIT license that is available here.