I found the scenarios now. It seems a little counterintuitive to have them ingame instead of in the game setup.
Maybe the scenarios could be included in the custom game settings. Another idea would be to make another menu at the main menu and call them FfH Campaigns instead of scenarios (so that are not mistaken or mixed with Vanila or other mods). Either of these ideas would make more sense then the ingame option that is the only way to reach them now.
I do like that a player CAN access them from ingame. I just think that there should be a way to start a scenario without first starting a game.