I would use the hardest local dark chocolate I could find that does not melt easily as the other ingredients are quite sweet already and you don't need more sweetness.
However, as I'm advising hard chocolate, microwaving will be out of the question and as you're a beginner, I would melt the chocolate "Au bain marie" instead:
Nearly fill a big kettle with water and submerge a second smaller kettle inside it and then put the chocolate inside kettle 2 and put the entire contraption on your stove. Please ensure the inner kettle has a lid on it so that no moisture from the boiling water gets into the chocolate!
Once the chocolate has melted, try putting your pinky in the melted chocolate: if you can keep your pinky in the chocolate for 5 seconds without burning yourself, it's at the right temperature. ;-) If you have a thermometer, let it cool down to above whatever the melting point was (measure while melting: it depends on the chocolate.)
Take a soup spoon full of chocolate and put the ball inside and then drip some more chocolate on top with a coffee spoon: this will not only make it easier for a first try, but will also look good as you'll get that "dripped" home-made effect.
If you have good moulds, fill them half up with chocolate, then put your ball inside and then close them: the ball should now be encased in chocolate.
Whichever method you use: put them in the fridge for cooling down and take them out one hour before serving.