Be really specific and if theres already a post about this please point me in the right direction
The patch should guide you through the process.
Before you install a patch though, I recommend you copy Battlezone 2 (that means select the battlezone 2 folder in program files, press ctrl+C, and copy it somewhere, rename it, and move it back to program files. You should especially make a new copy of battlezone 2 if you're going to install a beta patch.
Once you've got the copy of BZII you want to install over, download the install patch, and see where it downloads to. Then, double-click the patch installer. It should give you the directory of bzII to install to. If not, it should be easy enough to browse to the battlezone II folder you want to install over. Select that folder, and enter. Then you can proceed with the installation process. It's pretty much completely automatic.
And there you have it.