Add your Oreos to a food processor and pulse about 5 - 7 times, or until they form large crumbs.
Run the food processor and drizzle in the melted butter. Add a pinch of salt, if needed. (see notes on salt).
Pour the crumbs into your cheesecake pan.
Press the crumbs into the sides of the pan first, then into the edges and bottom of the pan.
You should add a pinch of salt if you are using Oreo flavors that are very sweet, like the birthday cake flavor. This will enhance the flavor, while subduing the sweetness just a little. Pressing the crumbs into the sides first ensures you get an even and sturdy crust all around as opposed to accidentally using most of your crust on the bottom and having just a little for the sides.