Example code:
node-node_key = c_nodekey-new1.
node-relatkey = c_nodekey-child1.
node-n_image = '@0P@'.
node-relatship = cl_gui_list_tree=>relat_last_child.
append node to node_table.
item-node_key = c_nodekey-new1.
item-item_name = '1'.
item-class = cl_gui_list_tree=>item_class_text.
item-length = 23.
item-usebgcolor = 'X'.
item-text = 'Sample Text'.
append item to item_table.