The default motor commutation values for IRB6000 & IRB6400 robots is 1.5708 (radians). The resolvers are set to this position when installed in the motors and should not be changed. The fine calibration is the resolver position relative to (or offset from) the zero crossing. Enter the fine calibration offset numbers from the sticker in parameters: System Parameters/Manipulator/Motors and then select IRB1. Cursor to cal offset and press enter, then enter the value from the sticker and press enter again. Cursor down one to valid cal offset, select yes and the press OK. Repeat for IRB2 thru IRB6.
The IRB2000/3000 and the M94A IRB2400/3400 had feedback units (resolvers) that were attached to the back of the motor and replaced separately from the motor. Commutation was much more involved.
Though not a "S4 for Dummies", this pocket reference may help you find other things easier: https://www.robot-forum.com/robotforum/man…ach;attach=7713