Evaluation of Section 508 in source selections?

How is everyone handling Section 508 requirements as part of source selections? I've heard that my agency is just now coming around and saying that we need to be including an evaluation of Section 508 conformance in all IT buys and no other office I've ever worked in has ever considered it. The issue is that it doesn't seem anyone I've talked to in the office understands when it needs to be evaluated, what we need to ask for, and how we evaluate it! I've looked on SAM.gov for how others are doing it but I'm falling short of finding more than one or two examples but they seem so generic. 

I see that the Section 508 website has language and instruction but I can't quite make the jump from what it says to how to actually implement any of it or how it would look.