It's exactly what it sounds like; coffee with spices in.
To make it, it's best to make filter or cafetiere coffee. Instant will still be ok, but not as nice because you'll have bits floating in it. Simply add ground spices to the coffee beans, then make the coffee as normal, with whatever milk/sugar combination you prefer.
As to what spices and how much, that's entirely up to you. I use about quarter of a teaspoon each of ginger, cinnamon and nutmeg. I feel like sweet spices are good in this, but I would have thought a bit of chilli would go well if you like it hot.
It makes a very tasty, warming, somewhat festive drink.