Since you ordered it from Midway, and considering the cost you have already paid, provided you have not used them I would return them.
You'll end up paying S/H; but you can return them via USPS and do it for about 5 dollars. The reason I say this, is that not only are you going to need a trim die, but you will still have to trim them in a normal case trimmer, chamfer the mouths, thin the necks, and then load. You will be much ahead of it all if you just buy the brass.
Case forming is not terribly difficult, but I agree with Hairtrigger, there is no need to waste time on forming brass if a commercial supply is available, unless you just have that much free time laying around.