fuel pressure regulator replacement instructions please?

This could be a number of things. First and foremost we need to check the fuel pressure as I suspect you have a regulator issue. Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Also, here is a guide that will help with black smoke in general:

https://www.2carpros.com/articles/engine-black-smoke

The other possible cause is a leaking injector. So we need the fuel pressure because if you have high pressure then the regulator could be the issue but the pressure may be slightly low and with black smoke would indicate a leaking injector.

https://www.2carpros.com/articles/how-to-replace-a-fuel-injector

Below is how to replace the regulator as I suspect that is the issue.

Hello, I'm Danny.

There is a strong possibility that the fuel pressure regulator is stuck open causing a rich condition that is giving you the black smoke-rough running condition from extremely high fuel pressure. The fuel pressure regulator is located within the in-tank electric fuel pump assembly. Here is a tutorial showing how to check fuel pressure. The fuel pressure specification for your truck is with key on-engine off is 55-62 PSI.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here is a tutorial showing how to replace an in-tank fuel pump:

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

I've attached picture steps below showing how to remove and replace the fuel pump on your truck. Hope this helps and thanks for using 2CarPros.