Brake pedal goes to the floor. Help!!!

[klwebb]

Hey y'all. A few days ago I noticed my brake pedal moving a lot more than usual towards the floor, and every once and a while it would go all the way and I still wouldn't be stopped. If I pumped it a few times it would help but still not how it should be. I put some more brake fluid in and I thought that fixed the problem but it started acting up again today. I'm guessing i need to bleed the lines? But I have no clue how to do that. I'm not going to be driving it until it's 100% fixed, I could barely stop in time when I was parking in my driveway. It's got power brakes and power steering w a 350/350 combo if that helps at all. I'm still pretty new to the truck game and I'm learning as I go. Thanks in advance!!