newborn sleeping arrangements

Lorna
So we have this Graco pack and play for our room for baby in the beginning. It comes with this newborn napper on the right and a changing table on the left. Do any of you use the newborn napper for them to sleep in? Or just put them on the pack and play mattress. The napper just seems too squishy and flimsy and I have heard newborns need more firm for SIDS prevention.