Use the “Search Board” at the top of each page for previously asked questions & answers
example:
If you have a WDTV Live Hub: http://community.wdc.com/t5/WD-TV-Live-Hub-Themes/Complete-Noob-Question/td-p/141088
If you have a WDTV Live Streaming Media Player (SMP): http://community.wdc.com/t5/WD-TV-Live-Hub-Themes/Easiest-Way-to-Install-Themes/m-p/427664/highlight/true#M8308