If you are not already proficient with RPN I’d think you would be better off using a third party application that removes the need for detailed RPN work. Sure it can be learnt but I agree with @Crunchmeister71 i hate having to use it simply because it forces you to think in a completely different way to how most of our brains have been trained. I can use it but do so only when absolutely necessary and then with gritted teeth. If you are still determined to give it a go the MSFS SDK pages have some useful reference material as a starting point.