I'D LIKE TO WRITE SOME MUSIC, BUT HOW DOES THIS THING WORK?

AS A RECOVERING TECHNOPHOBE, IE, I STILL HAVE NIGHTMARES ABOUT DOS, I AM A MUSICIAN WHO HAS HAPPILY CIRCUMVENTED THE ENTIRE LAST QUARTER CENTURY, WHEN IT COMES TO MUSIC TECHNOLOGY. I WASN'T HERE. NOW THAT I HAVE RETURNED, I AM TRYING TO COME TO TERMS WITH ALL THIS STUFF I HAVE PURCHASED ON EBAY, SOME WITHOUT ANY INSTRUCTIONS. THOSE OF YOU WHO WERE BORN WHEN SAMPLERS, SYNTHS & SEQUENCERS WERE A PART OF THE LANGUAGE, WOULD HAVE NO APPRECIATION FOR THE PROBLEMS OF THE AGED, TECHNICALLY ILLITERATE MUSICIAN, AND WHAT THEY MUST FACE. I HAVE AN ELECTRONIC ENGINEERING BACKGROUND, BUT WHEN I MOVED INTO MANAGEMENT 20 YEARS AGO, ANY REAL UNDERSTANDING OF CURRENT TECHNOLOGY WENT DOWN THE TOILET. ALL I WANT TO KNOW, IS, HOW DOES THIS BLOODY THING WORK? I THINK I HAVE BEEN DUDDED ON EBAY AGAIN!