There are 2 methods to stencil concrete , the first is trowelling a paper stencil into wet concrete then colouring over the top. The concrete can then be finished in several ways to provide a non slip finish. When the concrete is hard enough the stencil is pulled out to reveal one of several pattern options and then sealed. This method is rarely used today even though it provided a relatively durable non slip surface.
The second method is to pour a plain grey slab, wait until it is cured ( gone hard ) and then tape off lines or stick a full stencil over the surface. A 2 part coloured coating often referred to as cover-crete can then be sprayed over the stencil. The Stencil is then removed to reveal your pattern or design and sealed.
Although we have extensive experience in the first method we rarely do this finish. Occasionally I see a new adaptation of this product that looks OK but in general tastes have moved on. Personally I think it has a bit of a tired shopping mall look about it.