No doubt, after all this hard work, you're salivating at the idea of biting into your own chocolate bar. However, you're not quite there yet. Tempering is what makes chocolate shiny and gives it that distinctive snap when you take a bite. It also keeps the chocolate from melting as easily. To make a long story short, tempering reduces the cocoa butter crystals to an even, uniform size. You'll either need to put your chocolate mixture in the oven at a very low temperature or use a double boiler. Make sure to keep everything dry, because water is the enemy of chocolate. It will cause it to crystallize in big, uneven chunks.
Heat the chocolate to about 120 degrees Fahrenheit, and then allow the temperature to cool down to 100 degrees. Keep the batch at that temperature, but remove about a third of it and place it on your marble slab. This will allow the chocolate to cool quickly. Mix it with a spatula by folding it over onto itself several times. The chocolate should thicken up and drop down to about 85 degrees. This part is called the "seed chocolate" because the cooling process allows it to form even crystals. Add some of the 100-degree chocolate to the seed batch until it has thinned and you can easily work it again, and then mix the entire thing back into the whole batch of chocolate. At this point, check the temperature of the batch. It should be around 90 degrees. If it's much higher, the seed chocolate part will probably melt. It will probably take a few tries to get it just right; the great thing is that you can just re-melt and try it again if your first go at tempering doesn't work. Poorly-tempered chocolate can still taste good, but it might not have all of the qualities of chocolate that you're used to experiencing.
Once your chocolate is tempered, it's (finally) time to mold. Pour the chocolate into the molds you've chosen, and then tap them lightly on your countertop to remove any bubbles. If you want to toss in some toasted nuts, dried fruit or other add-ins, now's the time. Cool the chocolate at room temperature -- the fridge or freezer can introduce moisture. When correctly tempered, the chocolate should be easy to unmold and will be nice and shiny. If you didn't get it right (and if you didn't put in any nuts, of course), you can always try to temper it again.
It's been a long and arduous process, but you finally have your own personal chocolates. Expect the accolades to roll in -- and for people to start putting in special requests.