How to sight in a Tasco 3-7x20 scope with a Crosman 2100 multi pump?

Is your 2100 a plastic or metal receiver? The last one I bought was plastic and it flexed too much to hold a scope stable. I ordered a 2100b metal reciever from crosman and switched it out. Other than that it shouldn't be difficult. On the vertical clockwise lowers the impact, counterclockwise raises impact. On the horizontal clockwise moves impact left, counterclockwise moves it right.