Your first Input module that resides in Slot 4 (Not 3)if an 32 x input module will have addresses I0.0-I0.7,I1.0-I1.7,I2.0-I2.7 and I3.0-I3.7, The next module will follow suit accordanly, if for an example an 32 x Output module, Q4.0-Q4.7,Q5.0-Q5.7 etcetc
I is for Inputs,
Q for Outputs,
do read your manuals with the software, in the help menus, In the Hardware config the table will also list accessable addresses,
I don't know if this is what you are looking for but if you have a specific question we will all try and help !!
Mylo