Making soil from scratch

Hey everyone, this is my first post on here and I have some questions about making garden soil. Currently my farm has extremely poor soil, to the point that practically nothing but pine trees and bermuda grass will grow. It is probably about 95% clay and 5% quartz. I have been composting all winter in my chicken coup and have a decent amount of organic material but not near enough to do what I want to do. I started a garden approx 30'X40' and broke up all the clay and dirt and removed it to about 12" deep. I went and got many bags of peet moss, "top soil", composted manure, composted mushrooms, cricket crap, vermiculite and the compost from my chicken coup. I am pretty sure this will help give me nutrients and organic material to fill the garden back up with but I dont know what kind if any inorganic material I should add to my mix. Should I add sand and clay or anything else or just leave it with what i have already? Any help is appreciated.