design a forum registration form

This project is supposed to allow customers perform self-registrations using an online form that will ask for first name, last name, and mobile number. System will generate a 4-digit OTP and sms this code to the client (SMS Gateway will be provided) - then after the customer inputs the correct OTP, system prompts customer to select from 1 to 6 seats. The system should remember the phone number that the booking came from, in case of multiple bookings, the maximum ceiling of 6 tickets must be put in consideration. The system should generate a 6 characters random booking reference, and SMS this to the client and of course save it to the database.