The "assembler's" answer is that all you do is drive the two pins through and adjust trigger weight of pull. However, there is far more that goes into it than that. After Market triggers do not all have the same pick up point on the sear bar as the Remington did and since triggers vary from trigger to trigger in some brands (not Jewell for past few years), you may not have as much firing pin fall as you need. Also if the sear bar pickup point is too far forward, the cocking piece will follow the bolt closing cam until it picks up on the sear bar. The if you leave the trigger cocked and open bolt you will notice that it stops at the extraction cam-that means if you actually fire the rifle and start opening bolt-the trigger will cock prematurely and the firing pin will stop moving, then as bolt opening continues you hit the extraction cam and then the nose of the cp again-no you not only need to extract the case-but start a compressed spring and stationary firing pin moving again.
Yeah--there is nothing to it! Just install the two pins, pull trigger and gun goes bang--However, as you can see it does not mean everything is working correctly!
There is .05 to .06 variation between brands on cp pickup point!
Jim