This is a SkyProc based patch, you will need to copy and paste the jar located in your download into:
skyrimDataSkyProc
PatchersPauldronGreavesPauldronGreavesPatcher.jar
Then execute it.
If you don't, then the only way to get pauldorns, greaves and cuirasses will be through crafting.
In terms of order, recommend executing this after GELO and before REproccer.
An always run SkyProc patches after wrye bash.

As for where the ESP's go in the load order the base file should be bunched with your other items mods.
Exact order shouldn't matter since SkyProc handles leveled list merging.
The final ESP should be at the bottom of your load order with your other skyproc patches, in order of patching.