Okay, I may be one of the only people who use the microwave. But it's easy. I put the chocolate melts into the coffee cup, about 3/4 full. Put it in the microwave and wait 20-30 seconds, pull it out and stir them. They won't be melted, but you want to keep them moving. Put it in again for another 15 seconds or so, pull them out... they should start to lose their shape. You will see the edges melting away into blobs. At this point, you want to mix really well. Toss them around in the cup, get them moving. If your chocolate starts to melt even more and you can't see the shapes anymore, don't put it back in the microwave.
But if they aren't melting, put them back in. Another 10-15 seconds and pull them out, mix again, help them melt by moving them around and constantly mixing. This will make your chocolate super smooth, not burnt and ready to color!
Get TINY TINY TINY drops of the black coloring and put them in one at a time, mix into the chocolate really well. Keep adding TINY bits of color until you get the result you want. It's important not to make charcoal brains! :)