Soo today me and a friend notice that the KHC rooms they were off/not avaible soo me and this friend decide to create(firstly he did the room) a room and we noticed that when some one of us enters the created room we get this "Failed to connect to host" or it was something like that...

Can some body explain me how to create a room soo that the other person or maybe more people can enter and play

You need to open / portforward your port on your router, input and output. On the client (your friend) and host (you) side.
That's the main reason people get "Can't connect to host" error.

Or you can simply join KHC official rooms. It's not like they're overcrowded anyways ^^".

yeah i know but when the KHC rooms are off ( like the other day ) we couldnt play, so is there a tutorial for port forwarding/opening a port for PPD or some instructions....maybe............ please ^^

It depends of your router. Every router has a different UI.
Thought, if you googled "port forward" you would have found the http://portforward.com/ website which has a tutorial for nearly every router out there.