c3p = Construct 3 Project
And i don't know how to export the game yet.
Viewing post in What games can i use to publish on itch?
Well, if you can't figure it out, ask in General Development. But the export command shouldn't be hard to find, it's pretty important.
However, this page from the Construct 3 manual says the export option is under Menu->Project. I just tried it online, and it's there.