If I understand your post correctly, it's sounds like what you want is a primer on "beginning synthesis" of the "basics of synthesis," but it's hard to be sure without knowing which terms in the XP manual are giving you trouble.
I do think Keyboard magazine has something of this sort; certainly they have had numerous column series over the years dealing with it. Try going to their website
http://www.keyboardmag.com and snooping around, especially in publications, and if you don't find anything, email one of the editors and ask for some suggestions.