This server is solely for test code. You should have received an email with your login information to the server.
You can connect via SSH or use SCP or SFTP to transfer files. Whatever files you put in your public_html will show up under code.directdigitalllc.com/~yourusername/
A MySQL database has already been set up for you on this server, the database tables created, and data imported. The only things you need to write are PHP, SQL, and HTML.
You can connect to the database (named sample) with the username readonly and the password readonly.
If you have any questions, feel free to contact me. firstname.lastname@example.org.