Use the Insert menu to insert items onto existing nodes. The Insert menu contains the following options:
Inserts a new node to the right of the highlighted node. For example, Insert Before inserts Child 1.5 before Child 2.
Inserts a new node to the left of the highlighted node. For example, Insert After inserts Child 3 after Child 2.
Inserts a new node at a level above the current node. For example, Insert Above inserts Grandparent at a level above Parent.
Inserts a new node at a level below the current node. For example, Insert Below inserts Grandchild at a level below Child 2.