With Shiloh it's always easiest to call them. Last time I looked they only listed a part of the system on their website for some reason.
Basically there is this big piece that is like a frame that screws into your press. The second part of the seater is a short chunk of barrel that has been chambered with the Shiloh reamer ( no rifling in the barrel chunk, just a smooth bore ). You stick the bullet into the case so it just sits there and then you "chamber" it into the barrel chunk. Insert that into the frame that is screwed into the press and work the lever and it seats the bullet. Then you extract the shell from the barrel chunk with a small screwdriver.
The only thing that's slightly tricky is that when you first get the unit, you have to customize the seater for your bullet type ( you can get extra pieces if you want to use multiple bullet nose types ). You do this by making a dummy round with as close to zero runout as you can get, then you use JB Weld and a release agent ( I use imperial sizing wax ) to fit the nose part of the seater to your bullet. It's easier than my poor description makes it sound. It comes with good instructions.
The best way is to call up and ask about it though.
I did find a picture of it on the internet in a Mike Venturino article. I'm not sure why they aren't talked about a lot on the forums because they do work very well. I like it much more than my Redding Competition seater for instance.
Anyway this article has a small picture of the setup:
https://loaddata.com/articles/PDF/match%20BPCR.pdf
Chris.