Create a folder, put your file(s) into it that you want to share. Then go to LW's Library window, then menu File>Add folder to share & direct it to where your folder you just created is & select it.
Definitions of video formats: Go here:
http://www.pcwebopedia.com/TERM/A/AVI.html & type in the extension; eg: avi or mpeg, etc. Click on any links for xtra explanation
Also see:
autogenerated spam results & also
Movie download issues