You can melt the Ghirardelli dark chocolate melts in the microwave. Just follow the instructions on the bag. I melted them on a the stove in a pan as I don't like using the microwave too much. Low heat, stir, don't overheat or it will seize. Make sure no water touches your pan or it will seize.
Once the chocolate is melted, take your Oreos and dip half of it in the dark chocolate.
Set them aside to cool and set slightly and melt your Ghirardelli white chocolate melts the same way you did your dark chocolate wafers.</
Once the dark chocolate is slightly set, dip the other half in the white chocolate. You should have a small v shape of the cookie still showing.
Set aside and once the white chocolate is slightly set, dip it again in the white chocolate. This will give it an even coat and will make the white chocolate opaque.