To add a divider, ensure that you are logged in to your account. From the buttons at the top of the screen click 'Insert Divider'. Enter the name of your new divider and click save.
You can rearrange your work under each divider by clicking 'Move'.
Dividers automatically appear as filters for logged out users. You can see how this will look when you're logged in by clicking 'Preview' on the top bar.