From Workbench

An icon will be opened and zmachine will prompt you for a game name. If you have not assigned LTOI: to adirectory, you must type in the full name of the file you wish to run. If you are you using zmachine with the LTOI: assign and directory structure mentioned in the Hard Disk Installation notes above, you can just type the name of the games directory that you wish to play. For example: if you type `moonmist', ZMachine will attempt to open: LTOI:moonmist/Story.Data as the game file. From then on, the default SAVE/RESTORE path will be LTOI:moonmist, this way, you don't get a whole bunch of files from different games getting mixed up in your LTOI: directory.