When you are ready to add phone numbers to be blocked from calls or SMS on your child's device which you own and have proper consent to monitor, simply go to the interface and click Options > Restrictions > Block List Contacts. Then you will see a screen called Block List. Click Options > Add > Number.
You should enter each phone number exactly as it appears when that person calls or texts. For example, if a number looks like 212-555-5555 when it's called, then that's how it should look in the call list. If it looks like 555-5555 then that's how it should look. If you aren't sure you can put any variety of ways the number might look including:
If a number is in the Contacts list, you can easily block it by clicking Options > Add > Contact. Then choose the contact and that contact's number will be inserted automatically.
After you are finished with the additions, click the Back button and then Home.