Insert existing drawing into other drawing set

In simple terms if was trying to create a drawing as a set ofa engine, hence adding new sheets as i was doing the engine block& heads; for example, though if i was going to use a pistonthat i had already done a drawing that was done & was anidependant drawing, how do i insert it into the set so i will showup down the bootom as an added sheet with a tab, so i canultimately include this into a PDF complete folder of parts.SolidworksDrawings And Detailing