The brick walls must be clean and sound. After any cleaning you will need to prime the brick with a good acrylic masonry primer. After that you can paint. Or you can use a masonry sealer instead of primer and paint. Masonry sealers can be clear, semi-transparent or solid colors just like exterior wood stains.
The floor is basically the same but it will need acid etching before applying anything. For a painted look use either a solid concrete stain or epoxy floor coating. Clear sealers can also be applied.