Be sure to release all pressure in the fuel system before servicing the fuel injectors, as it is always under pressure, even when the engine isn't on. The first thing to do is open the engine cover and air cleaner assembly before you remove any fuel injectors. After that, remove the fuel rail assembly. After removing the clips that fasten the injector(s) to the fuel rail, pull each injector out of the fuel rail. Prior to insertion, use a little engine oil on the O-rings of each fuel injector. After that, fit the injector(s) and injector clip(s) onto the fuel rail and then put the fuel rail assembly back in place. Return the air cleaner to its original spot, fire up the engine and check around for any leaks. Only then install the engine cover.