Hi Linda! There are many wonderful sites out there to help you. Take a look and see if these help! Good luck on your project. If you can, I would love to see your finished project.
Here's a video that shows you how to stencil a concrete floor: https://www.youtube.com/watch?v=9PbxoF2OPl4
Linda: Maybe this will help --
Here are two projects that I have done - one with a stencil and the other is with a roller - https://www.artisticpaintingstudio.com/?s=concrete+floor