Install this awesome theme as normal. Place the nice-and-clean-theme directory in your themes directory, such as ~/.config/awesome/themes, and update your rc.lua file:
beautiful.init("path/to/themes/nice-and-clean-theme/theme.lua")
Widgets are done with native awesome wiboxes. They may not work with your awesome version (my version is 3.4.5). Weather widget is done using conkyForecast script (not included in this package).
Note: RAM usage and CPU usage widgets are not updated automatically because I update them from my statusbar Vicious widgets (to consume less resources). To make them independent you should rewrite their body so they parse files /proc/cpuinfo, /proc/meminfo and temperature themselves.
Calendar and todo is done using https://awesome.naquadah.org/wiki/Orglendar_widget . You can scroll the calendar to switch months.
Inspired by https://awesome.naquadah.org/wiki/Nice_and_Clean_Theme .