Do these tiles need to be glued down on concrete to prevent them from moving? I’d like to put them on stamped concrete walkway which is pretty smooth on the surface. I’d prefer to not glue them if it’s not necessary.

Our 1" Safe-Play Tiles are installed with dowels that hold the tiles together, so you wouldn't need glue to install these. However, our 2.5" and 3.5" tiles are installed with glue to hold the flooring together. You could use the 1" tiles for your walkway.