What's left looks like shelled walnuts. Next, the nibs are roasted. Since roasting brings out more of the chocolate flavor, the details of the roasting process are kept under wraps. The roasted nibs go into a grinder. The friction of the huge grinding machines causes the cocoa butter in the nibs to melt.
Cocoa butter is a vegetable fat that looks like caramel.
After the the cocoa butter is removed, a thick paste is left. Though it looks like smooth dark chocolate, it tastes very bitter. The liquor can be hardened to make unsweetened baking chocolate. Or it can be pressed to remove still more cocoa butter and then pulverized into cocoa powder. It's called conching because the machines that do the conching used to look like giant conch shells.