Please explain in detail would be appreiciated

Uhh… it… java containers? Umm… You’ve got me! I don’t know!

You sound like you mean what’s it about, so here’s the about page:

https://itch.io/docs/general/about

If i’m way off, my next hope is that the Getting Started page is exactly the thing you’re after:

https://itch.io/docs/creators/getting-started

If that fails, i’ve failed you.

after creating a game, you typically submit binaries (compiled code) to run on different systems (typically windows, mac, and some variant/variants of linux, to make it accessible for most)
if it is not a video game, it is up to you how to submit. In the future, give more information in you question.