Nesting is done through the tree structure in the Level List window "> Help | Kubotek3D

Nesting of Levels
KeyCreator \ View \ Level \ Overview \ Nesting-of-Levels

Nesting is done through the tree structure in the Level List window (i.e. each level has one parent on a higher nesting level, and the top-most levels nest under the database itself). Nested levels are not functionally different from first-rank levels. A theoretically unlimited number of nestings can be created.