twm boots up with just the terminal, called xterm, open. xterm is used to launch all other programs by pressing the t key. The button in the top left of the window turns it into an icon, minimizing it. The button in the top right is supposed to be used to resize the window in actual twm, but that's not possible in Scratch. If you click on the desktop, it opens up the twm menu, which is used to close programs and open the xterm (if you closed it by typing in "exit"). Currently, the list of programs is: xclock - Simple clock program. The time shown isn't accurate xcalc - Calculator program. You click on it to do a calculation xterm - The terminal. You press T to type a command.
This is an operating system emulation of a Unix OS in 1987 using twm (Tab Window Manager). Note that this isn't THE Unix OS; Unix is a family of operating systems, and not all of them use twm. Infact, Mac OS is actually a Unix operating system. I couldn't find out what specific Unix OS used TWM, so I just called it this. twm is also available for Linux and Minix.
