You should not rush manamune just buy the tear and next buy brutalizer you could rush it first making it to a black cleaver or get bloodthirster first your choice and iceborn should be bought after completing black cleaver and blood thirster and next is iceborn but you can buy it first early in the game so you can counter against more stronger adr than Lucian and lastly buy the spirit of lizard elder or guardian angel if what kind of position your in and just buy a dorans or a long sword and 2 pots for the starting.