No brake pedal

Does the truck have anti-lock brakes, and did you allow the brake fluid reservoir to run empty? If so, you will need a scanner to command the ABS computer to open two valves so those chambers in the hydraulic controller can be bled.

Check out this article for more suggestions:

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Yes it does have ABS. A brake line broke and the master did run dry. Can I use a scanner from an auto parts store to do this?

Generally not. They typically just use a code reader that reads fault codes in engine computers and sometimes ABS computers and airbag computers. They do not allow for bi-directional communication, meaning the ability to talk back to those computers and command them to do things. Also, you will need to open two bleeder screws while doing the procedure. Every time I have done this, it has been the two right bleeder screws. Once you start the procedure, it is over too quickly to even get excited. You will be done in a few seconds.

Do I use some sort of power bleeder?

Nope. I have not used a bleeder ball since the 1980's. I only do gravity-bleeding, particularly because I am usually doing that by myself. Also, it is real easy to damage a master cylinder by pushing the brake pedal more than half way to the floor, and I do not trust helpers to avoid doing that.

In this case you are usually instructed by the scanner to press a button on it, then to push the brake pedal. That initiates a sequence where the pump runs and it opens two "apply" valves. That purges the air from those two chambers and runs enough brake fluid to get any air to the bleeder screws. No pedal pumping required.