Validation with FB Groups?

Hey guys finally taking some action and trying to validate with Fb groups (free traffic) my niche.

I just told people in some niche related groups that I will give them a free ebook and people opted-in.

So then in the ebook there is a call to action button to get people into my own niche group.

I've got 80 people into the group so far.

So what would be the best way to validate fast?

I mean can I keep giving value in my group to people and then ask people if they want a video course?...

Validation with FB Groups?

from Validation with FB Groups?