Place your wooden box in an area that is convenient for pouring and making the molds. It will likely be too heavy to move once you are done making your molds.
Select some items of which to make molds. You can also freehand the mold; it just depends on what you want to make. Pick simple shapes and manageable sizes that can be easily lifted and manipulated.
Fill the wooden box 2/3 of the way full of damp sand. You can pour dry sand in, then wet it and stir it with the trowel. The sand should not be so wet that it is slippery and muddy, but it should be thoroughly damp so that it holds its shape when it is patted or pressed.
Smooth the top of the sand. This makes a smooth, even surface for your mold. Use your hand or the side of the trowel.
Press the objects that you wish to make molds of into the sand. If you prefer, you can make your own shapes in the sand using your hands or the trowel. A popular mold is to carve out a circle or square, then press your hand into the center. This will make a pretty and personalized patio stone.
Once you have finished designing your molds and removed the objects from the sand, you are ready to pour your molding medium into the sand. When the medium has set, simply remove it from the sand and rinse it off to reveal your unique work of art.