You should start from reading documentation of ShapeEditor class. In particular to finish shape AxMap.ShapeEditor.SaveChanges should be called. New shape is started automatically on the first mouse click after the previous one was saved or discarded (ShapeEditor.Clear). AfterShapeEditEvent event is fired automatically by ShapeEditor.SaveChanges (as far as I remember). UndoList can be a bit tricky, but MWLite has good samples of its usage (MergeOperation.cs, ExplodeOperation.cs). Trial and error approach is the best way to master it.
Hope it helps,
Sergei
Hope it helps,
Sergei