In your admin go to Appearance > Menus
If your used to wordpress menus, the design of Arrastta isn’t much different.
You add menu items on the left, and they show up in a list on the right.
So if you want to add a category to your menu, click on “category”, type in your category then click on the “+” and the category will automatically be added to the list.
You can also add custom links.
You can also rearrange the order by grabbing a menu box and dragging into your desired place.