With one side secured, go to the other side…start in the middle, and pull it nice and tight as you go.
Now the corners. Cut off any felt that is obviously excess material, and wrap it just a little way into the pocket to get a feel for it, and make sure you like the way it looks.
Cut a downward slit in the center of the pocket, and then one on both sides of the first so that you have three slits. Make sure to start your slits below the bottom edge of the slate, (1/2 inch) or you will end up with gaps in the felt that will show on the edge.
Another view of the slits
Once you’ve made the cuts, just wrap the felt underneath, and press it firmly into the glue on the bottom of the slate.