Crap day today so I'm Youtubing a bit. This one by ScannerDanner is excellent. Although you can do this type of test using a Tech 2, if you don't have one, this is an alternative but you still need an injector tester, which is available on Amazon for about $35US.
US:
https://www.amazon.com/dp/B06W2MP3JF/?tag=gmtnation-20
Canada:
https://www.amazon.ca/dp/B0126MEK3C/?tag=gmtnation-20
And if you want to get fancy, you could go to a yard and get a fuel injector harness connector from a junker for easy connections.
US:
https://www.amazon.com/dp/B06W2MP3JF/?tag=gmtnation-20
Canada:
https://www.amazon.ca/dp/B0126MEK3C/?tag=gmtnation-20
And if you want to get fancy, you could go to a yard and get a fuel injector harness connector from a junker for easy connections.