New grass grows slowly in the spring because the ground is still cool. You’ll see some grass in a week, but seeding in spring is often a waste because the summer heat will kill the new grass. You are better off planting in the late summer or early fall.
I find that raking the seeds in and covering with a 1/4” of Peat moss does the trick. Keeps it moist and grass explodes, but again, better in late summer when it starts to cool. Need about a month or so before first frost for grass to get thick.