Set out clean and dry chocolate molds on to a cookie sheet that's been lined with parchment paper.
In a double boiler or microwave, melt the chocolates according to the packaged directions. I like using a makeshift double boiler--a glass bowl over a pot that's big enough for it to rest on top of and leave room for the water below.
For the add-ins to be on top of the chocolates, sprinkle them evenly in the bottom of the molds first (this will be the top after removal). Use a spoon to fill the mold with your desired chocolate. Be careful not to overfill. Use a table knife or scraper to smooth the chocolate. If you want chopped nuts, fruit, or sprinkles inside the chocolates, you'll need to mix them together first in small bowl before adding to the mold.
I did something different in each cavity mold. I alternated the chocolates, did a chocolate swirl (chocolate and white), layered the chocolates, and changed up the sprinkles and peppermint.
Once you've filled all of your molds, place the cookie sheet in the fridge for 15 minutes for the chocolate to harden. The chocolates will slip out easily of the molds, and you're ready to package.