Which tank first?

[Brendon25]

I recently bought a water softener setup with two tanks but don't know which tank should be first in line. One tank has a color digital readout and comes with the regeneration line for the brine tank and the other tank has a black digital screen. They are commers brand out of Minnesota. I can't find an answer readily available online and commers won't get you answers unless they send someone out to the house. Any help is appreciated. Picture attached.

 

[Reach4]

Softener is usually second.
Looks like Technetics / Logix / Autotrol.

Find a manual. The inputs/outputs may differ from some other softners. So watch the in and out.