Questions about gst

(business of trading of iron steel in u.p.)1.what will be the balance stock and how much tax will be paid after gst,suppose we have stock of 1 lac then what tax will be paid by us? 2.If we purchase the material from out of u.p state and sell it out of u.p. then what tax will be paid by us? 3.what will be the facility and benefits for those traders whose sale above 60 lacs? 4.What will be the forms as 38,C,H,F and 21?Pls give me the answers in details.