I use a small pointed artist trowel or a brush to put it on. Smooth out the snow as best as you can. After you apply the glitter you can pat it down even smoother with the back of the trowel, your finger tip or other small tool. The glitter is somewhat like sprinkling flour on dough, now the tool won't stick to the snow so it is even easier to get a smoother surface. After it dries if there are any high spots or funny peaky bits you can gently knock them off. You can put more paste on top of a previous layer and more glitter should you feel the need to rework an area.
Keep your snow in scale with the size of your building. On my little cardstock buildings the modeling past did not make the paper soggy, it dried fairly quickly.
My Etsy store is now open for buying the paper village kits.