I am really confused as to the difference between the two. created a basic metronome and they use hot and cold inlets like a lot of pd projects, but I've no idea what they do. any suggested readings or maybe quick explanations?

Pd's control examples (in the help browser) are probably the best resource for this sort of thing.

i just did up a tutorial, hope it helps:

http://puredata.hurleur.com/sujet-6381-hot-cold-inlets-execution-order-trigger

perfect! thanks much. that tutorial made perfect sense, was much needed. kudos!