arrange in the sequence you would find them in a plant starting from the periphery- phellem, phelloderm, phellogen

Phellem i.e cork forms outermost layer.
Then comes cork cambium i.e phellogen.
And the cells of phellogen cut the cells below it into secondary cortex called phelloderm. Hence, from periphery, phellem-phellogen-phelloderm.

Hope it helps