This is for siblings currently using one email account in myCBDR - normally a parent's email address.
The second sibling needs to register for myCBDR using a different email account - can be the other parent's email address.
After you approve the request and they receive the instructions to log in to myCBDR.
Once there are two email addresses and two accounts in CBDR for the two children, you activate myWAPPS via myCBDR app for each child using the matching email address for myCBDR.
They will receive the instructions for myWAPPs app. They choose to log in with their hemophilia app and link to myCBDR.
If there are more than two siblings then again each one will need a different email address as above.