Installing small concrete slab.?

I am trying to take the easiest route possible I work at a hardware store so I get stepping stones at a very low discounted price. I was wondering if there is anyway to put down the stepping stones to where they would not move. A grill will be going on top of these so they need to be very stable. Or would it be easier just to build my own small slab? If so could you direct me to a website with good instructions explaining every step. Any other solutions will be very helpful. Thanks!