How do gain 17 lbs of muscle quickly ( about 2 1/2 to 3 months)?

im 5 ft 7 the now and 8st 2". i want to gain 17lbs of muscle,this builds for rugby and athletics, not shot putt but like 1,2 and 4 hundred meters plus javelin. kinda like a inside centre or open-side flanker build ( fast but strong ). So if you could give me a gym plans or a diet or some tips to gain this muscle FAST . THANKSs