No need to identify yet, but collect as many odd, unique, colorful, eye catching, distictive rocks as possible. Ask friends, neighbors, family members, look in barns, gardens, basements, garages, while on hikes, while hunting or visit a tailings pile at a mine site.
You'll need many to fulfill the requirement of 2 each of sedimentary, metamorphic and igneous plus 4 different minerals. No 2 can be the same, so that means 10 different specimens that satisfy the above criteria. Many rocks/minerals look very different but in reality are the same thing. You can't collect too many! Get busy.