One method to open the Windows Explorer begins with Clicking on the Start button found in the lower left corner of the screen. -- A submenu (called affectionately 'The Start Submenu') will appear.

Move the mouse to highlight the Programs Option -- another submenu (called 'The Programs Submenu') will appear.

Typically at the bottom of this submenu you will find the option "Windows Explorer". Click on this option. That will open the Windows Explorer window.