Complex sentence: The Winter Olympic Games don't always have a central Olympic Stadium, however some past games have, early Winter Games often used figure skating venues as focal points and were designated as the Olympic Stadium, which usually hosts the opening and closing ceremonies.
Split into simpler sentences: The Winter Olympic Games don't always have a central Olympic Stadium; however, some past games have. Early Winter Games often used figure skating venues as focal points and were designated as the Olympic Stadium, which usually hosted the opening and closing ceremonies.