I am surprised you are unable to find the bars. If you let me know where you are located, perhaps I can help you find it.
If you plan to melt chocolate, it's best to buy it in bars. Chips contain less cocoa butter so that they can better hold their shape in cookies, but this makes them harder to melt and less tasty. It's easiest to melt chocolate in a microwave oven. Just break the chocolate into small pieces, heat it for 30 seconds at 50% power, stir, then repeat a few times. Take it out of the microwave when the chocolate is almost completely melted, then continue stirring until the melting is complete. If you don't have a microwave, use a double boiler.