Got to love free crypto.
So i went through your link and because I've completed the beginners lessons my only option was to invite 4 people, and so I presume the invite (and $10 per person) only works for up to 4 people who haven't done these lessons.
Good luck on earning your $40.
Ahh, yea if it comes down to it I can get family to do it, but would love some instant gratification, haha.
At least you got some backup. I think I'll be struggling to catch the 4 here and would settle for 1!