Upstart is made up of items and files. A file is just that: some data that you have on your computer. An item is a set of file(s) that you put together and upload. You can give your item a title. You can give it a description. You can publish it for others to see. You can sell it. An item could be simple: just a single picture, or video. Or, it could be a several related files, like an song with album art, lyrics, and a music video. Craft items to suit your needs.
We provide a mostly what-you-see-is-what-you-get interface for editing your item in preparation for publication. We offer some unique features you may want to take advantage of, which are covered here.