Extracting a year, month, or day number from a date isn't something you can do with basic arithmetic. But Excel has functions — a system that takes something as input and produces a new output. Think of functions less like math equations and more like machines: feed in raw material, get something useful out.
Let's extract the year first. Click the top cell in the Year column.
All formulas start with an equals sign in a non-Japanese (half-width) input mode. Type = and then the first few letters