How do I do it??

Zander pretty much did the day time toilet training on his own, but I have no idea how to go about night-times. He can have his day sleep with undies on without a problem, just does a wee before & after he goes to bed. He's waking up of a morning now barely wet, maybe one wee in his nappy whereas a few weeks ago he was waking up soaked. So how do I teach him about not weeing overnight, or getting up to go to the loo / potty in the dark?? He doesn't like leaving his room of a night once all the lights are of......