Choosing the menu option File > New runs the File Setup wizard. This is a simple step by step process with full instructions on each step. You can open more than one set of accounts if you wish. This is useful if, for example, you are a treasurer of a club and also want to keep your personal accounts.
Each set of accounts that you open needs a name and a place to save. Use the Back and Next buttons to step through the wizard. The last step of the wizard gives you an option to run the import setup wizard should you choose to start the file with data loaded from a spreadsheet. See Initial Data Import for more details of how that wizard works.