To install, unzip into your CAVEDOG\TOTALA directory, and everything should go where it should. 

Be advised, you need the 3.1 patch, and you should have the CORE CONTINGENCY expansion pack for this unitpack to run properly (although it is not essentail, the hovercraft will not work without it). Also remove any other 3rd party units, as they will more than likely conflict with these.
Have a blast!