Here is a recent thread of mine that talks about serpentine belt... not exactly your question but pics worth 1,000 words as they say.
The other sources worth getting signed up for are Cummins Quick Serve...threads with specifics in Cummins section and
Freightliner DTNA. Likewise discussions in FL section.
I found little info on specifics for engine accys like alternator, AC compressor, belts belts via Cummins I'm guessing because they are determined by the chassis builder and can vary.
If you look into the parts sections of these links you can find some systems with diagrams and part numbers.