First you need to download and install this Style. If it works, you can install the Portal for this Style as per description:
copy: root/ext/board3/portal/styles/prosilver/template/portal/*.* to: root/ext/board3/portal/styles/aero/template/portal/*.* copy: root/ext/board3/portal/styles/prosilver/theme/portal.css to: root/ext/board3/portal/styles/aero/theme/portal.css copy: root/ext/board3/portal/styles/prosilver/theme/images/portal/*.* to: root/ext/board3/portal/styles/aero/theme/images/portal/*.*
In the end "ACP -> General" --> purge cache
It's recommended to purge your browser cache too.