Questions about building muscle/burning fat?

I am an adult male who currently owns a pull-up bar and am hoping that I can build muscle with this piece of equipment. My questions are: Is it REALLY possible to build significant muscle with a pull-up bar? If I incorporate cardio into my routine, will that be counter-productive to building muscle? I'm just confused about this and don't really know how to go about things. I can't afford a gym membership or expensive equipment. so the pull-up bar is my only option at this point.