The downloaded .zip file contains everything that is needed to install it on a Deluge SD card.
Copy it on SD card root and unzip it. On macOS and with some tools the archive gets extracted in a new directory with the same file name.
In such cases move the directory content up one folder and remove the new (now empty) directory to clean things out.
Download a full Deluge repository
While browsing Deluge content select a repository (by clicking on the second synth or kit subtitle). You're now viewing the content from a specific repository
Click the repository name on the title. You're redirected to the repository's GitHub page
Click the Code menu and choose the Download ZIP action
Index a new Deluge repository
Sharing new kits, songs and synth patches requires publishing them on GitHub as a repository and adding it to Delugist.
Once you've added a GitHub repository you can keep adding Deluge resources to it, and these will be automatically indexed in Delugist.
To setup a new GitHub repository for sharing Deluge content see specific instructions.