I was called by a manager a week and a half after applying. Due to covid it was a one on one interview with a manager. Usually you are taken to the shop floor with a manager to see how you interact with customers.
Knowledge of current trends are imperative, such as upcoming tech products that may lead to increased sales. Knowledge of specific areas, such as audio equipment, phones, kitchen appliances, home furnishings etc are important as it makes you stand out from other applicants. You need to be enthusiastic, willing to go the extra mile to help customers.