The previous answers are correct, you will receive and email and sms and also you can check the status here on your profile.
To track the status of your invited friends, and know the amount of the referral bonus you'll receive (or referral bonuses if several of your friends activated their plan using your referral code) :
To see the referral bonuses that were applied to your payments, check your Transaction history.
The previous answers are correct.
You should see the referral as pending on your account.
After your second monthly payment, the referral will show as earned and you will receive an email confirming it.
And the referral credit wll be applied towards your future renewal(s).