Welcome to the forum! One thing you should definitely get for him is a heater. :) Bettas are tropical and should be kept in water between 78 and 82F.
Make sure that the water movement from the filter and airstone don't bother him. Bettas come from very sedentary, low-oxygen water in the wild, and are not amazing swimmers due to their long fins, so can be freaked out by strong or fast water movement.
If you can, more plants or ornaments for him to explore and hide in will help keep him contented. Bettas are curious and love to explore.
Watch out for discolouration, lethargy, lack of appetite, paleness, bloating, fungus, black edges to his fins, tears in his fins, red marks and white dots. Those are all signs of illness of some kind of another.