How do you make file download and upload for image, video, files etc?

hello again,
i am making graphic design assets and 3d models and I'm planning to make an app for people to download files from app preview them for free and also there will be option for puvlic to become contributor so anyone can suvmit files for free and a donation button for contributors wil add income to them
any sample project like this will be helpful for me to startup as im also learning blender and unity, side by side
one more thing i would like help from you is is there any block coding available like mit app for PC?
thank you members

Generally, you would use the web component to facilitate downloads and uploads within an App Inventor app.

Exactly how you do this will depend on your online storage location.