Wetherspoon is a pub which serves food. They are known for being cheap and family friendly. You would mainly be working in the kitchens or doing bar work.
It is important to make sure that just because the pub is cheap, it does not mean that it does not want to give good customer service. You will need to show at interview that you will be welcoming and friendly to the customers. You will probably be asked for examples of when you were in certain situations and what you did in them. You may need to think of ways that you have helped people. They may ask you how to deal with complaints as well, such as a customer complains about the food but has already eaten most of it. You may also be asked to think about how you would sell a customer a dessert. Consider different scenarios and questions that you might get so that you are prepared for answering them. You may also have to explain how you will cope with the job if you do not have relevant experience, so would need to explain that you are a quick learner and enthusiastic and perhaps show how your past experience might help you.
They may want some bar experience, but they do take on people who have had none and will train you up, by allowing you to work alongside someone else. This means that it is important to demonstrate that you are a good learner and willing to take instruction. They sometimes prefer inexperienced people so that they can train them in their ways and so you could use that as a selling point. If you are working in the kitchens they may prefer more experience though and so be prepared for that.
They may ask you how many hours you want and what days you want to work. Be honest because if you are not, then you could get stuck with hours that do not really suit you. You want to make sure that you are happy. Pub hours can be from breakfast time until the early hours of the morning, depending on the branch and so you need to consider what you can do, especially if you are fitting it around another job, a course or a family.