Not sure I fully understand what phpmyadmin does.
I created a database in phpmyadmin, and would now like to start accessing the data in it from php. However I have no idea where the database is?
Should I export in the phpmyadmin software? I tried that but it came up with a .sql file which can be opened in notepad and contains the SQL statements used to create the datbase and the one table inside. Basically that doesn't look like a database to me.
phpMyAdmin is just an interface to work with an existing MySQL database server. However you have configured phpMyAdmin to access the MySQL database is the same information you need to access it through PHP. You will need the server name/ip, username and password.
There are many tutorials available online that can help you get started.