The following code shows how to create a new category and a bar item, and assign the item to the category:
using DevExpress.XtraBars;
//...
BarManagerCategory category = barManager1.Categories.Add("Development");
BarItem item = new BarButtonItem(barManager1, "Tool1");
item.Category = category;
//customize the item and add it to a bar/menu
//...
Imports DevExpress.XtraBars
'...
Dim category As BarManagerCategory = barManager1.Categories.Add("Development")
Dim item As BarItem = new BarButtonItem(barManager1, "Tool1")
item.Category = category
'customize the item and add it to a bar/menu
'...