You cover the cookies with flood texture royal icing (I do mine to about the 15 second rule - I can explain more if you'd like me to). Then let dry about 6 hours.
You'll use a stiff royal icing to cover the stencil with. Make sure you scrape excess off and then lift up. This was the firs time I used a stencil and I flubbed up several.
Then I decorated them with mini rosettes (stiff texture).