This is beyond simple.
Fill a small trashcan or other bucket with water and leave out over night. In the morning it should be frozen part way through on top and sides but not the bottom. Run hot water on it till it releases from the mold. If the bottom is at all frozen tap it until it breaks and let the water out. The photo shows the trash can DIY one on the left and a store bought mold on the right. The mold from the store has a small pocket of air in the middle that stops the bottom of the mold from freezing. Now make a bunch and line your steps. Better yet build a 15' snow pile and place it on top forming a lighthouse or something.