The OT Installer for Mac OS is available as a zip archive which is most conveniently extracted by double-clicking on the file in a Finder window - one of these can be opened from the directory where the archive is located by typing open . on the command line. The actual installer is called ``almaot'' (a command line ls will show that this is a directory called ``almaot.app'') and can also be opened by double-clicking. Note that this will probably bring up a dialogue box saying that the application cannot be opened due to it being from an unidentified developer. In order to overcome this one must open the ``Security & Privacy'' section of ``System Preferences'' and enable the installer there. This might need to be done even if the dialogue box does not mention the reason for the failure to run the installer.
Once the installer has been started it will bring up a succession of dialogue boxes which will guide you through the very simple install procedure - see Figure 2.1. In most cases one will just need to click ``Next'' several times. The default install location is the Applications directory with a shortcut created on the Desktop - double-clicking this will start the OT.