From the main screen of the application, select the room in which your light is placed then – if need be – select the light by pressing on it.

In the center of the screen just below the list of your lights, tap to open the light mode selector. From that window you can access any of the light modes, as well as the custom color selector to dial the color you like. Press on a light mode to select it.

This works with a room, but also of course for a group or a single lamp. Just follow the same process to apply any light mode whenever you want.