By the way, I figured this out and I'd be glad to propose an addition to the wiki to help out newbs like me. Let me know if you want it and I'll post it below.
Thanks for this wiki, but I think I need just a little more help. (on Mac) I had thought an engine came with the install, but I might have deleted it. I tried unistalling and reinstalling ChessX but that didn't work. Am I remembering that correctly? If I do need to install one, could you point me to one that you recommend, and is the simplest to install? It looks like Stockfish may be problemmatic and you said "just the fetch the source code and build stockfish yourself", but I'm not sure how to...