I bought Night Terrace online, where do I download it?

Depends where you bought it. These articles should help:

About Ben

Actor, writer and game designer Ben McKenzie is one of the co-creators of Night Terrace. He serves as a producer, writer and actor, playing the part of the gormless Eddie Jones. His other well-known works include the PlayStation VR game Table of Tales: The Crooked Crown and the monthly Terry Pratchett podcast Pratchat.