Are payouts paid right away after the winning?
Yes.
~snip
why you do not just make video tutorials about how to play or bet in ethex.bet?
if you make video tutorials then it will be easy for new users to understand how to play it
That is a decent idea, however it is fairly easy, you have videos on how to use metamask and is pretty self explanatory.
There is "rules" as soon as you enter the site.