Jemasco Compost and Manure????

spring is around the corner and im getting a head start on grow site preparation, the soil is horrible. there is two inches at most of top soil then its six inches tiny rocks and sand followed by clay. so im thinking since im only growing ten plants (5 northern lights and 5 swiss cheese) i'll make ten 1 cubic raised beds using jemasco compost and manure.
has anyone ever used this brand? i looked it up and all its made of is manure, bark, and sand.
is this a good mix? if not what should i add that i can easily pick off the ground?
any information will be greatly helpful.

peace and happy tokin