Once you have gathered your materials, spread out the parchment paper and drizzle different sizes of hot glue all over the surface. Allow to dry completely before removing. Meanwhile, take your fairy lights and bend the wire into straight vertical lines to create stems with a light on each end. Then cover the stem with hot glue and hold it upright. A simple thin layer is enough. Once the wire is bent into multiple stems, remove a small amount from the parchment paper and apply hot glue to the ends of the wire stems. And voila! There is a very cute mushroom light.
You can also create a more detailed display using materials like faux moss from Walmart, flat glass beads from Amazon, and wood plaques from Michaels. To replicate @infinitecreativity_'s work, glue the faux moss to the mirror frame and hot glue the mushroom stems onto the moss, one at a time. This creates the appearance of small mushrooms growing on the mirror. Or, to create a centerpiece, take a wooden board and glue artificial moss (or any other foliage of your choice) to its surface. Next, hot glue flat marbles along the moss, followed by fairy light mushrooms. The wire glued to the leaf will be exposed, but you can leave it as is or cover it with additional flat marbles.