Different Maps and Units

How do you create a game with different maps or different units? I've played in them but then when I go to start a new game it's only the regular options.

Do you want to host such a game or to 'create/make your new' map?

To create a new map from scratch with your own map background, units, countries and cities, go to the MAPS tab in the top right corner. Click the green NEW MAP button on the top right.

To host a game on a custom map, go to the MAPS tab in the top right corner. Filter or search for a specific map/scenario/preset if you want. Click on it's image and then again the green "Start new game" button. Enjoy!