Hi & welcome to the forum. I’m just one of the testers, not a dev, but until one of them passes by, I can confirm that help is always needed, especially from gamers who like testing.
This is where you can find the download link to the latest release. As explained there, after downloading the archive you only need to extract the files into your Heroes folder (where WoG 3.58f should be already installed). This does not mean VCMI will interfere with H3 or WoG versions of the game, so no worries there.
And this is where you can report the bugs you encounter.
Of course, there is also a Polish version of the forum, so you can report bugs there as well if you prefer (though I won’t deny I could use another fellow tester here in the English section).
Cheers and hope you’ll like what the devs have done so far to stick around!