Here's my take. You put the thing at the right height, set up horizontal with the bolt, push it out so it the outer part of the cage lines up with the big ring, our a bit further. Clamp cable and check if the big ring trim position lines up with the derailleur (these mystery white marks, that's what they're for).
If you get it there, or close enough you can just get there with the tension bolt just proceed with setting limits and check. If you can't get there unbolt the cable and add or release tension.