If you would like to turn on Template hits and block names in the admin panel this can be quickly done via the database.

INSERT INTO core_config_data (scope, scope_id, path, VALUE)
VALUES ('default', 0, 'dev/debug/template_hints', 1),
('default', 0, 'dev/debug/template_hints_blocks', 1);

Note, don’t forget to add your prefix if you are using one.

To turn this off once you are done, either delete these rows from the database, or set the values to 0. (If you set them to 0 you can later reactivate this by just swapping it back to 1, but the insert statement won’t work any more.