For changing the outlets, all you need to do is unscrew the receptacle from the electrical box, and then unscrew the wires from the receptacle. As the wires are stiff, you should have a pair of pliers to bend the tip of the wire to replace it around the screws of the new receptacle. Make sure that the individual wires in the Romex (a black hot wire, a white neutral wire and a bare ground wire)are attached to the correct screw in the receptacle. (When you remove the old receptacle, note which wire is connected to which screw.) It takes all of five minutes.
And for God's sake, make sure the power is off!
And when you check that the power is off, check BOTH plug outlets in the receptacle. You could have a split duplex receptacle. In other words, each plug outlet could be powered separately with its own wire. You need to turn off two breakers for a split duplex.
