Do you have any tips on how I can engage a beta group that is testing my product to extract the most valid information?

I'm trying to find out if you have any tips on how I can engage this beta group and extract as much information as possible so I can really hone in on that viable, what that minimum viable product is. I don't know if I would...how big is the beta group? So there's 30 families now, so 60 individuals...