Hello everyone!

I recently bought an 8x10 camera and it came with a Rodenstock Makro-Sironar 210mm/5.6 lens, in a compur 3 shutter (1/200 max speed).
I could not find any manuals for this, and i'm not a 100% sure on how to use this lens correctly. The rear elment has a marking for 1/3 to 1 and the front element is marked 1 to 3 magnification.
I'm i supposed to swap the elements, or just use the rear cell for 1/3 magnification?

Here is an image of the lens: Click image for larger version.  Name: IMG_20211030_192943.jpg  Views: 43  Size: 46.0 KB  ID: 220858