You change a newborn's diaper as often as they go pee or poop. or as close as possible. sitting in poop or pee will burn their skin and cause a rash. it hurts too.
I would expect to change baby when they wake up, most will go pee at least then.
when they eat, especially when nursing after a bit they may go poop, so you could try waiting for that to change to cut down on the diapers that only last 15 minutes.
but at first, expect to go thru at least 12 diapers a day if feeding is going well, and things are moving along as they should.