Please just be honest because I don’t get the joke

It’s common to make it flatter if fills in any divots, you have to have good soil in the first place for the seed to grow. If there’s a lot of clay in the soil sand helps water not sit on top and rot the lawn out either, Canadian here that helps the thaw in the spring but if you get salt on your lawn it’ll probably die anyways. If you want more info there’s other steps too, like thatching - removing old dead roots and aerating - spike rollers basically that stabs holes in the ground without uprooting the grass