Locate the fuel injector you wish to test, you do not need to remove the injector to test
Now locate the wire clip. Each plug has one of these.
Press this wire clip in towards the injector and then wiggle and pull the plug. Do not pull on the wires.
Set your test meter to 12v DC and test the voltage between the fuel injector control circuit and ground. Should be battery voltage.
If you do not have battery voltage or very close to it, there is a problem with the wiring.