Not sure I follow -- there are certainly many primitives that must be defined by the host to bootstrap that are not special forms -- starting with list, cons/conj...
I doubt there’s a guide anywhere: it’s far from a trivial undertaking. If you want to look at the Java code that builds all the primitives, see the Clojure/Lang folder:
Part of what makes it Clojure instead of just a Java-based lisp are the persistent data structures that allow for efficient immutability, and the seq interface for working with collections smoothly. There’s a big (scary, to my eyes) set of classes that underlies all of the convenience. Thankfully it’s very stable so I don’t have to think about it.