Liverpool are gearing up for their first Champions League game for more than 18 months on Tuesday. The Reds have a long and famous history in Europe’s premier competition, but had to settle for a spot in the Europa League last season. But as a result of Jurgen Klopp’s side finishing third in the Premier League, Liverpool are back at the top table this time around. For head coach Arne Slot, it represents a Champions League debut with Liverpool and as far as tests go, they don’t come too much trickier than a trip to San Siro. And with the Reds preparing to face AC Milan, sporting director Richar…