Start with drawing out your design on some tracing paper. If you are doing anything with lettering such as our logo as shown below, you don't have to worry about reversing them because the stamp will create the same image as you are drawing.
On a thick sheet of clay pressed onto a tile so it doesn't slip, place your drawing over the clay and lightly trace over the image with a pointed tool to create a light impression.
Pull the paper away and with your tool, go over the impression several times to make a deeper impression. Try to use the same pressure so all of the impressions are of the same depth.
Trim the excess clay away, leaving the carved piece on the tile to bake. Bake following your clay package instructions. After your piece is cooled, sand it with wet/dry sandpaper until it is smooth and level. You have now created your "mould" to make your stamp.
Now take a medium-thick sheet of clay and press the clay into your mould to create a reversed image.
Press this piece of clay onto a ceramic tile and carefully cut around the letters. Do not remove it from the tile or it will distort and bake this piece.
Shape a piece of clay and attach it to the back of your stamp to make a handle. Bake this piece again.
You may need to lightly sand your stamp to make a smooth impression (which naturally I have not done yet here!) Anyhow, Voila! Your stamp is now ready to use!