Materials:
Large drill bit or boring bit.
Saw
sandpaper
measuring device
hammer and small brad nails (or nail gun). I suppose you could use wood glue too :)
Safety gear always recommended (eye protection, mask for sanding...)

2. Mark your spots for your holes. I made mine with three candles and spaced the candles out evenly. I then added a bit more space for the plant. You only need to mark and drill the top piece of wood.
3. Drill your holes! Get some sample tealights and make your holes slightly larger than the diameter of the tealights. I also drilled a larger hole for my mini-flowerpot. 

4. Sand the entire thing. You can technically choose to sand before fixing the two boards together. It depends on if you want both sides and all edges of the boards sanded.

Obviously you can use any type of finish or paste wax on this. Your call. Enjoy!