Thanks, just got the notification
I believe you're already past the "find friend" step since you clicked on my direct link (that was just another way of doing the same thing.)
I'm looking and I think you can click on "my friend referred me" then "enter account info" and put in the same email you claimed with - but until all lines are active it may show "You haven't claimed your offer yet but there's still time! Please check your email and claim your offer to proceed." Once its all activated you can try that again and it may allow you to enter the new #'s there.
If not, try this:
After you're all activated, open up the email you got today (Activate now to get your Reward was the subject last time I did it.) Then click on #2 which says "Come back and register your new Sprint mobile number." There it should allow you to enter each of the new phone numbers and/or the new account number. You basically are just registering your new lines so it knows this has all been completed.
(Also - says "You must agree to receive Program-related emails and accept the Program Terms & Conditions when claiming your offer." - not sure if that was a required checkbox when accepting, but something to confirm.)
If you need any other help you can PM me, thanks!