There are three questions to ask
1.really, How to do referral program?
2.how to get referrals?
3.Does it profitable?
BTC
1. I found that we can give referral mining link or referral code. Both of them at pure mining, not cloud mining.
2. Ask your friend to mining like you, then you give him your referral link or referral code.
3. Not sure. But, if you have much more referrals maybe profitable.