To create a space, press the icon on the right of the status bar. There are a number of fields to customize your space on the New Space creation page. Pick a logo for your space, name your space and choose a display label, write a description for your space. To create your space press the icon. It will now appear in your Spaces list.
There are a number of permissions available when you create a space.
You can customize the notifications members receive when someone posts in the space, you can limit who can add new members to the space, and limit who can post or reply without permission.
For a step by step demonstration, click here.