Since your staff is not going to be expert at every question that comes their way, giving them some help is important.
Most helpdesks start with a trouble tracking system.
These systems do not require any AI, as they are essentially databases with time triggers. However, most of these systems ask that problem description and problem resolution information be entered into the database. From there, it seems a logical next step would be to leverage all that typing and use the information as a primitive knowledge base . Unfortunately, while the users are all different, the questions called in seldom are. This happy thought has occurred to more people than just you.