Creating a storage type website

Hello,

I would like to make a website, in which people could upload and download files. It should be possible to search for various files and sort them by category. Registration is optional.

For example: https://cubehero.com/

The thing is, I know HTML/CSS and some Javascript(so I can style my webpage), but my understanding on how to implement various back-end functions to a website is lacking. So it would be great, if someone could offer me an advice on what plugins or themes to use.

Thank you very much for your help and advice.