Create game wizard
It can be found under both the single-player and multi-player tabs. Under multi-player, simply click the Create Game sub-tab. Under single-player, click the large green Practice Game button.
 Choosing a template
You can choose to use any of the built-in single or multiplayer templates or one of your own saved multiplayer or single player templates.
 Choosing a map
There are over 1200 maps to choose from and they're in several categories.
 Customizing settings
It's possible to customize settings from a template that you've choose, or you can make your own custom game from scratch.