Hopefully this is not too out of date; Goldenflame Dragon posted an announcement to the Ultima Dragons Discord server at the end of March. However, on the assumption that the Google Form still being open means he still needs volunteers, here’s what’s happening:

Hello and welcome, prospective beta testers! 

If you’re here, you probably know as much as you need to about the game. But here are some other things you should know.

Logistics

I only need so many beta testers, but I may need them in a couple of waves- mostly if I set up what I think will be enough, and then half of them report they don’t have time to keep up with it. So, if you submit this form you are not guaranteed to be called upon to test. 
The Beta test will be Windows only. Down the road there are plans for there to be mac and linux builds, but this is not that day.

My hope is that the beta testers will play through the entire game. I will be looking for feedback on balance, on unclear direction, and of course on bugs.

You will need to play with the developer’s console open. Instructions will be provided for how to activate that and where to find the information I need if you hit any major bugs. I may sometimes ask you to email me your saved game directory. I’ll give you details on all this if you wind up testing.

If you’re interested in testing out The Dark Unknown, head on over to this Google Form survey and fill it out. Goldenflame is only welcoming so many testers at once, but may swap new testers in as others drop out.