some 1 plz teel me how to program this or just program it for me?

it is a kind of claculator

(step 1) " you wish to sell __[A]__ items for __[B]__ each"
(step 2){conformation} "So you wish to sellyour items for __[B]__ each and for a total of __[C]__" thats alli just need "[A]" to be multiplied by "[B]" to get "[C]" and for the second step i just need "[B]" to be inserted into the second slot for "[B]"..... it seems confusing but it is just a price checker... it could really help me