Where do my shims go ?


I tore down my used Torment 4x4 and didn’t take note of where my shims were in my diffs. It’s a used Torment so I don’t know if the shims are factory installed or if they were installed by the previous owner.
Unless I lost one, which I don’t believe I did, there was 5 in total. I believe 3 in one diff and 2 in the other. Just can’t confirm it.
Where do these get installed during the diff assembly and how do I know what diff they came from or how many went in each ?
Is there a diff shimming 101 class ? Do I check for play to trial and error where they came from and how many ?
Lessons learned for a first timer. I guess this is how we learn sometimes ?