Create custom API plugin for Wordpress

I have a website that needs to have custom plugin built out. This plugin will have API integration into Booker dashboard, that will allow us to schedule appointments for our client from our website and have them integrated in our [login to view URL] account. Here is a link to Booker Api Doc: [login to view URL] Here are requirements that we will need to have in this plugin: 1) Company representative should be able to register on our website with their @[login to view URL] email 2) Select a specific date assigned for their company/book it for X amount of hours (recurring booking on a weekly basis for the same date/time) 3) Once booking is complete to have a button to share the booking - this window will open the email of the user and have pre filled email content and subject line (all the user will need to is to enter email list) 4) With the link in the email - another user will be able to go on the website and register on the website/sign up for that specific date (user can sign up with the assigned company time only if the email @[login to view URL] of user matches the company registration @[login to view URL]) 5) Each account for company/parent account needs to have a credit card attached and children (employees) user accounts with their own credit card attached. Account needs to have ability for a Company to cover X% of the haircut. 6) In the checkout process there should be automatic process for TIPS - 10%, 15%, 20%. Once selected it should be automatic choice for the next appointment Repeat customer funnel (so pretty much login for users) Minimum 3 hours of booking appointments.