You have a lot of reading to do.
If you want to use https you will need to purchase a certificate, and unless you want to make your own life excessively complex you would then use IIS to create the initial website, and you could use ASPX to then make the web folder sharing ability.
Most of the web sharing thing doesnt work as a windows folder, it works more in the lines of a database of files - or it can work with a folder structure - but, you handle all the user authentification and settings yourself via a db.
Did I just hear "You gotta help us, Doc. We've tried nothin' and we're all out of ideas" ? Is this you? Dont let this be you! I will put in as much effort as you seem to.