Steps before processing T4s

Hello all,
I'm wondering if I can get some guidance on what things I need to check before I issue T4s in Sage 50?  I haven't done it before and there is no instructions from the previous person in my position.  I want to ensure that everything goes as smoothly as possible.

I've reconciled my government remittances and discovered a small discrepancy, but I'm not sure what else I need to do.


Thanks