I'm a Fedora 31 user. Following strictly the instructions to install the theme, I get this:

$ ./install.sh -d ~/.themes
cp: cannot stat '/home/mdamaceno/adementary-theme/src/cinnamon/cinnamon.css': No such file or directory

I realized the need to run the script ./render-assets.sh before running the above command.

Perhaps, the parser script must be included to the documentation.