I needed help installing xmllint from this website: http://xmlsoft.org/sources/win32/
In particular, I am not sure which file I am supposed to download - when I clic
The link from C.M. Sperberg-McQueen is a good starting point. You need to 1) download the libxml2 package, and 2) place the bin folder that comes with this in a directory contained in your PATH environmental variable.
If you don't know how to figure out which directories are in your PATH environmental variable follow this: http://www.computerhope.com/issues/ch000549.htm.