When making an initial purchase, please just purchase ONE time for ONE initial student. You will receive email instructions that let you self-register that initial student plus a teacher's account.
Then, to add additional siblings to the same course, log in with your teacher account and click on the name of the course (e.g. "Digital Savvy") to enter that course. Once you see the list of chapters down the middle of the page, look for the "Teacher Menu" on the left side.
The "Add Sibling" link will be near the bottom of your Teacher Menu. Complete the transaction through that "Add Sibling" link and your existing student registration code will be increased to accommodate additional student(s). You can then self-register the additional students and they will be automatically linked to your existing teacher account.
Please see the "Licensing and Multiple Students" section on our Conditions of Use page for licensing details on multiple siblings, unrelated students, and larger classroom environments!