Begin by placing some moss into the jar. Take a spoon and press the moss down so it is firmly packed into the jar.
Sprinkle some rocks in. We used small crafting pebbles but you can use ones from your own yard if you have them.
Add a little glue to the stems of your mushrooms. Glue the stems to the various pebbles. This is easier than trying to glue the mushrooms to the moss to make them stand in place.
Place the mushrooms and the rocks they are attached to in the jar. You can finish off the garden with a pinch of glitter if you wish or leave as is.