Here you can clearly see the components & construction of the frog shelter : the entrance, the back panel and the roof slate sandwiched at an angle between the back panel and the wall of the trough. I screwed 2 screws into the backpanel just under the tip of the slate and left them standing proud of the surface to support the slate and to prevent it from ever slipping down should the pallet wood distort.
I actually cut the roof slate to size as it is of natural slate and I was able to cut it using a hacksaw , keeping the blade doused with water as I sawed to prevent it from heating up due to friction and loosing its edge.
A REMINDER: FOR BOTH THE WELL BEING OF THE FROGS AND YOURSELF YOU ARE COMMITED TO USING ORGANIC METHODS OF GARDENING. THAT MEANS FOR INSTANCE USING ORGANIC COMPOST, NOT USING TOXIC SLUG PELLETS (usually Metaldehyde or methiocarb) OR CHEMICAL PLANT FOOD OR WEED KILLERS . YOU CAN FOR INSTANCE USE A LIQUID SEAWEED PLANT FOOD SO LONG AS YOU DILUTE IT CORRECTLY.