If successful in securing an interview you will be called and emailed to ensure you're aware and know where you're going. Once at interview you will be given a brief tour of the area in which you'll be working and then it's in to a room and down to business (with the offer of a brew). The interview consists of competency and STAR based questions so things like "Tell me a time where you had to give bad news to a customer" or "Where do you see yourself in x number of years?" There are of course role specific questions you'll also be asked. Thankfully, Zen seem pretty quick and aim to let you know one way or another.