When I create a game, how do I pick a colour?

I'm embarrassed to ask a stupid question, but I need answer please! So far I've only played anti - chess. The only icon that appears is split down the middle white / black; so far as I can see, there is no way to select only the white pieces or only the black pieces. What is the solution? and is the answer the same for all variants?

In the main lobby, click the "Create a Game" button.
On the bottom of the popup window are three button that allow you to select your choice of color.