Preping for a diff build and gear change. Questions.

I have all the parts for my new front diff build and rear gear swap, however, I am getting so conflicting info. I was going to buy some spare diff carrier side bearings to use as set up bearings for setting up shims however some articles I have read say the shims are on the outside of the bearing and not pressed on between the carrier and bearings.
Just looking for clarification before I wreck a good set of bearings .

Preping for a diff build and gear change. Questions.