You need to have sponsor link to get registered. Once you registered log in into your registered email id and click the link to activate the ID.
Click forgot password in the login page and a new password is sent to your registered e-mail id.
Yes once logged in with your login credentials you can go to settings and do the required changes.
Yes you can edit the name, address and phone number only after login into back office.
NO. E-mail id is unique to each account. Name and Phone number can be same for different accounts.