They're a fairly easy swap, the upper intake comes off, along with the vacuum lines (or you can be very creative and scoot the intake to either side when you move the rails.
Be sure to depressurize the rails or let the car sit overnight since the rails will have some pressure behind them if it was recently driven.
Once the upper is off/unbolted there are two bolts holding each rail to the lower. Take that off and pop each injector out of the rail and its wire clip and put the new ones in. I use a water-based lube on the o-rings to keep them from binding up when installed. Apply gentle pressure to the rail and pop each injector in and bolt it all back together.