I'm assuming that you have unzipped the file to say the desktop?

Simply click the file after you have unzipped it.

WinZip,WinRar are programs used for unzipping,I prefer WinRar because alot of the files from Bitzi are in (.rar format),not (.zip format).

When opening .jpeg,it should open in your photo editor program.

Movies will open in your media player program.