To use windex for applying a Monokote overlay, all you have to do is...

1. Cut out your overlay piece,
2. Make sure the base Monokote layer is clean and dust-free,
3. spray the base layer with windex,
4. Peel the backing from the overlay and lay the overlay piece over the base layer,
5. Position the overlay where it needs to be,
6. Squeegee any bubbles and as much moisture as you can out from under the overlay,
7. Let it dry -- at least overnight,
8. Seal it (using a COOL Monokote iron or by running solvent around the edges).

A couple things... First, until it's dried, you can peel it off and reposition it, so mistakes don't really matter. Second, you can use water with half a drop of liquid dish detergent instead of windex. Third, a scrap of balsa sheet makes a nice and resonably soft squeegee. Start sqeegee-ing it down in the middle and gradually, carefuully work your way outward. Fourth, if you use the iron, it should be heated just enough that the adhesive side of a scrap of Monokote sticks to it... not enough to shrink the covering at all. Otherwise the Monokote will emit a gass that will gather as ugly bubbles under your overlay.