@sviyagin has pretty much covered everything (seriously, I’m bookmarking it myself for future reference, lol), but there’s one thing I wanted to add to this question:
So yeah, as sviyagin said, a beta/playtesting period that is hosted on the forums (that is, the forums are the primary site of recruitment and updates) is a requirement to publication via Hosted Games. However, posting a publicly available demo (regardless of its length), shouldn’t just be seen as a means to an end or as purely functional, it’s also how you gain word-of-mouth.
Think of demos as advertisements, something for people to take notice and keep track of, to share to their friends. Successfully translating beta testing activity to into sales on launch can be tricky to pull off and is unfortunately not something that can be condensed or taught, it kinda has to be worked through to tailor it to your games’ needs and your personal means, but it’s definitely worth it to cultivate an internet presence prior to launch. Even a small preexisting fanbase can prove to be a boon for future sales and projects.
I’m currently on mobile so prexise examples will have to wait, but I hope this has been helpful nontheless.
And if you’re ever confused on something or need help with anything, you can always message me or any other mod and we’ll help you asap to the best of our abilities!
Welcome to the forum! 