As well as opening (connecting) to existing databases it is also possible to create new SQLite databases and tables using DB Browser.
To create a database click the New Database button from the main toolbar (also available from the File menu). You will initially be asked for a name for the database and where you want to save it. It is saved as a single file. If you do not provide an extension default, then a '.db' extension will be used. Although the new database is empty, in that there are no tables in it, the .db file itself is not empty.
Once you have saved the databae file the Create Table wizard will open allowing you to create a table. You can cancel this for now as we will be going through the create table process in a later episode.