SA44B measurement amplitude

Hello! My name is SungWon and I am a hardware engineer.
I am using the SA44B for our product, and I have some questions. The software development environment is Visual Studio 2015 and I am working with C ++.

First, how to set the frequency band to measure. I have read the API manual, but since I am a hardware engineer, it is a bit difficult to understand.

Second, what is the API function that reads Amplitude? Or how can I know the Amplitude value directly?

I refer to the API manuals and examples, but it is hard to understand what they are. I have also used the forum, but it is hard to know because I only have to look at the example.

Thank you!