Make sure you take a nap before your 1st night on, I take a 2 hour rest , which gets me thru the night.
Create a day sleep environment, room darkening curtains, turn off phones etc. If you have kids, turning off the phone could be a problem.
I don't have any trouble sleeping during the day, some nurses take benadryl, or other sleep rx.
If I'm tired at night when it's slow, I walk around the unit.