To create a BURST account need to visit burstoralcare.com
From here, you will choose “Not a member? Create an account.”
Once you have selected this you will be prompted to populate your details
After you have created an account, you will then click on the person icon again 
to log in or view your account.
From here you can make any additions you need, here are some super handy articles for any information you might need to add to a new account
How do I update my payment method with BURST?
How do I add my new shipping address with BURST?