Please avoid a manual install and use the GNOME Tweak Tool, it's much easier.
You can use the gnome-shell theme extension for easier switching of themes.
GNOME Tweak Tool
Make sure you have user-theme-extension installed. Load the GNOME Tweak Tool and go to Shell Extensions and click the "Use Theme Extension" switch. Now go to "Theme" and click the Shell Theme box and locate your theme zip. Now you can select the theme in the dropdown box.