with new cranks its simple, providing you have a torque wrench and some grease (i always used lithium grease) and apply the grease to the taper and slip on the crank. as dave said 40-45 Nm's is the recomended pressure for cranks, to little and you risk the crank working loose, too tight and you will destroy the angle which enables the cranks to stay locked in the same position on the taper. the grease is to make sure that the pressure is applied evenly up the shaft/taper and a MUST HAVE for any set of new cranks (or old, providing the threads are clean) is some threadlock, applied to the crank bolt and you shouldnt have any problems.