You could buy the stones at a hardware store
This article has a few different options that might be helpful: https://gardentherapy.ca/diy-concrete-stepping-stones/
I make my own square stones. Lay a sheet of plywood down on a level surface. Get some 2x4's and nail them together to make what ever size you like. I make 14 1/2' square. I get 18 per batch if I fill up the plywood. Then a wheel barrow and a few bags of ready mix...
Check that pin https://www.pinterest.com/pin/771311873671261354/
I’ve seen old cake pans used with waxed paper as a mold release.
Here are some ideas
This tutorial shows how to make pretty stepping stones with Quikcrete.
This is another good tutorial for making DIY concrete stepping stones.
Buy a bag of Post fix, mix in water and place in a mould of your choice. or form a shape on flat ground and pour in mix. Should be dry in a short time.
Hi Becky: Home Depot sells a reusable mold maker. You just put it on the ground and pour Quikcrete or add water to concrete mix and pour into your pathway stone molds and let it set up. That's all there is to it :) Here's the site for the forms:
There are loads of ways to do this. Try using the search bar at the top left, lots of great inspiration will pop up!
Here is how to make some that look more natural/uneven shapes: https://www.youtube.com/watch?v=MNaVzbwuATI
Hi Becky, hope this helps you out,