FileMaker 11 uses a different file extension and file format than does FileMaker 12 and 13. You can open a FileMaker 11 file (.fp7) using FIleMaker 13's Open option in it's File menu. This produces a new copy of your file converted to the newer .fmp12 file format. Once you have produced a converted copy, that .fmp12 copy of your file cannot be opened by FileMaker 11.
I would like to use the framwork of an existing database and create a new database using the same layout.
I can read that several different ways given that "database" might refer to a table, a file or a group of files, but if you use Save a copy as, you can make clone (no records) copy of your file and then you can modify that file's design as you see fit to create a new database design based on the data model of the original copy.