asp.net Caldav calendar sync project

I have a basic asp.net webforms app I have created that allows a user to log in and record appointments in a calendar which are then stored in an MSSQL database. I need someone to add a Caldav service to the app so that users can connect to it with their username and password to then have their calendar items from my app showing in their calendar. Using this means that if someone deletes, adds or changes an appointment in the app, it will update on their calendar on their device that they have set up to connect to caldav with For example, a user may have an Iphone and they would then go into the settings on the iPhone to set up a calendar account (as per [login to view URL]) I need this project completed within 14 days. This app is in asp.net 4.8 (webforms) with vb.net code behind and an MSSQL database. I will supply the app source code and sample database to whoever is working on the project so that they can add the caldav functionality to it.