Hi,
I found a typo in the instructions.
I also proposed an alternative method of installing dependencies which has the main advantage of marking them as automatically installed (not manually installed).
I do not know the equivalent procedure for non-Debian systems.
More details here: https://askubuntu.com/questions/101651/how-to-install-themes-with-gnome-tweak-tool/1128098#1128098
These suggestions also apply to the installation instructions on linux-apps.com: https://www.linux-apps.com/p/1136805/