To run Vahunz, you need an Amiga running at least AmigaOS 2.04, being equipped with an 68020 CPU. Memory requirements depend on the number and size of input files, but 1MB of free memory usually should be more than enough.
Installation itself is easy: Simply extract the archive to some directory where you will find it again, for example to Work:Vahunz.
If you want to use Vahunz from the CLI only, you have to add this directory to your search path. This is not required if you are satisfied with the functionality Vahunz-Tschak provides.