Introduction to GEM and TOS

The Atari TOS/GEM OS is mouse based, there are offcourse shortcuts you can use by a keycombination especialy in later TOS versions, but TOS/GEM is a mouse based OS. That means that you use the mouse for clicking menus, windows, messageboxes etc. Click on the menubar and you can move the window around. You can resize it, expand it to fill the screen, or make the windows go away, all with a few clicks of the mouse.