To open the Start menu, simply click on the button at the bottom labeled Start to open a large window with a variety of apps such as the Clock to check the time, the Music app to listen to the music available on the operating system, or even Settings to switch the interface between normal or black mode. To close any window, just click on the red close button usually located at the top. On the right, there is the terminal where you can type various commands to interact with the operating system and even replace the Start menu. There are several commands in the terminal, such as: settings, clock, music, informations (informations about), black UI, and normal UI. To stop the music, just click the power button again. After changing the interface to black UI, to return it to normal mode, just click the same button again. If you don't see the button close in the window of an app just reopen the app with the terminal!