By default, the ArrangeSiblingNodesAs property is exDefault Use the ArrangeSiblingNodesAs property to align horizontally or as tree the child nodes. Use the IndentSiblingX property to indent horizontally the sibling nodes. Use the IndentSiblingY property to indent vertically the sibling nodes. The IndentChild property retrieves or sets the amount, in pixels, that child nodes are indented relative to their parent nodes, which has effect if the ArrangeSiglingNodesAs property is exTree. Please notice that the assistant node is always aligned to the right, no matter of the Left property, if is a child of a node that has the ArrangeSiblingNodesAs property on exTree.

For instance, in the above screen shot,  the Item 1 has its child nodes as a tree, so the ArrangeSiblingNodesAs for this node is exTree. The Child 7, displays horizontally, its child nodes from left to right, so its ArrangeSiblingNodesAs property is exHorizontally, and the Child 16 arranges its child nodes vertically from top to bottom, so its ArrangeSiblingNodesAs property is exDefault. 

The following screen shot shows how the child nodes are arranged when the ArrangeSiblingNodesAs property is exDefault ( see the child nodes for the "Item 1" node ) :

The following screen shot shows how the child nodes are arranged when the ArrangeSiblingNodesAs property is exHorizontally ( see the child nodes for the "Item 1" node ) :