How to make a web front end to a FTP server?

I want to implement something like this [1] were clients can login, upload files, make directories, etc.

Couldn't find anything here [2] or after a quick DDG search.

I know how to setup an FTP server, a web server, and how to make a simple web page, but I don't know how to link the FTP server to the web page, basically. Furthermore, I don't know how to do it securely. The goal of the project is to let clients access this service and upload big files (>100GBs) reliably over the internet.

I don't know where to start. Also, I'm new to programming (basic Java experience). Could you guys help me out?

[1] https://ftpsite.vmware.com/login

[2] https://code.vmware.com/apis