What is the floor made of?
You didn't mention what type of floor, but I'm going to guess that it's a tile floor, but not ceramic. If that's true, here's a tutorial that you can follow to paint or stencil. If you don't want to stencil, just leave that section out. Basic steps are prep, clean, prime, paint and seal. I hope this helps you. Wishing you the best.
I'm not sure what kind of floor you have, but I painted my linoleum floor and you can check it out here:
Buy a quantity of Floor paint and and an extending roller + a paint roller tray, or a large brush and knee pads! Start at the farthest corner from the door and work towards the door, so you don't trap yourself in.............