If you get HSQLDB HyperSQL User Not Found Error when you connect with a blank user id, it may be necessary to connect with the default admin user. The default login information would be a user id of SA and a blank password.
If you have a single odt file, rename it to .zip and unpack it.
ODT databases should have database folder inside, with files
You can switch to 'Edit Manually' in the JDBC URL combo, and make sure the path is pointing correctly.