SMS Verification on register page (Osclass.org)

Greetings, I need a Registration page based on [login to view URL] that required user to verify their phone number. The SMS Verification will be based on [login to view URL] Things to be done: 1) Default "+673" on the phone number column, So when user input the phone number, they can't change/edit the country phone code. 2) When user create account, user need to input phone number, and verify their phone number (Need Verification code (NEXMO) from SMS before account is successfully registered) 3) Check database if the phone number is registered (if registered, error "Phone Number is Registered" ) 4) Limit Verification for every 5 minutes. (User need to wait for 5 minutes for second verification code) 5) Link to resend Verificaiton code after 5 minutes expired.