Dry brush wood with both colors of grey. Squirt a small amount of the lighter grey paint onto a plastic lid and squirt with a water bottle mixing water and paint with paint brush. Start with a lot of water; more paint can be added if it needs more color. Do the same thing with another brush using the darker grey paint. Use a small amount of diluted paint on brush and swipe across board going lightly so that the wood grain still comes thru. Start with lightest grey and then go back with the darker grey in a few places to give it an aged look. Repeat process until you have the desired look. Always better to start really light and then go back and add in more color as needed! Be sure to do all edges of wood panel not just the top flat surface.
After the grey has dried paint the red area with a dry brush and leave a few areas with less paint to give it a weathered look.
When paint is dry apply stencil. Peel off graph paper backing and center on the panel. Rub the paper with a credit card or bone folder. Peel off the opaque backing being careful that all the vinyl is sticking to the wood. When all the backing is off the vinyl flip the backing over and rub around on the vinyl to secure any loose edges.