What is router?

Pa beza nya router sama wireless kn? and pa beza nya Lan switch and hub? Hmm confuse ku eh sama ja function nya.Can anyone tell me what are da different between those devices and their functions...Makin Kusut ku ni makin buban th kepala ku ni memikirkn cna kn figure out to solve problem for my assignment.
Picture datas tu utk aku submit assignment ku network ahaha...