Teak, Ipe, or cypress would be the best non finished, weather resistant woods. Be aware those woods will naturally turn gray over time.

There really is little gain in making perfect joints when making outdoor wooden furniture, since weather makes the wood move enough to open joints. Good joints are enough.

Use stainless steel screws---predrilling is a good idea. If you use brass screws, you will have to predrill.

Round over top edges, but leave bottom edges square---that causes the water to drip off at the edge instead of wicking under the wood.

It might be a good idea to have any screws for the top to be underneath, not on top, exposed to the weather. That eliminates depressions that hold water.