This howto services as a temporary collection of documentation for common tasks, until we get a more extensive system in place.
Press the "Create New Character" button. Your new character will start in a world of his own, shapeless and without body, but as a free floating spirit. You can navigate around the room by clicking the left mouse button, but before you can do more meaningful things, you need a body.
To get a body, please speak with the plastic surgeon to your upper left in the room. Speak to him by clicking on him with the right mouse button. Speak with him again if you want to change gender.
Before you can walk the real world, you also need to choose a name for your character. To do that, speak with Germania, who is to your upper right. Once you have chosen both a body and a name, you can enter the world by way of the ladder to the far upper right in the room. The ladder is also to be right-clicked to be traversed.
Before you do that, however, you will probably want to have a look in the chest to the bottom right from your starting position for some clothes, basic tools, food and dreams. After that, you are free to roam the world as you see fit!