Unless you intentionally want users to be able to access DB files from any arbitrary location on their computer, you'd be better off storing the DB files in an application directory and letting users pick the DB from a simple ListView (which you would populate by iterating through all the DB files in your application's data directory or sub-directory).
For your second question, you should create a template database file with the correct tables, fields etc. but no data, and embed this as a resource in your application. To create a new database for the user, you would copy this resource to an actual file location (with the new DB's file name).