That would be it. Red and yellow make orange. Nothing else does, but you can try different shades of red and yellow and different amounts of each such as:
2/3 yellow + 1/3 red = regular orange
cadmium or hansa yellow + alizarine crimson = deep orange
lemon yellow + grumbacher red
Light/lemon yellow + bright red like vermillion = bright orange
Add brightness rather than white to create brights. For darks think of adding blues and purples rather than black.