Take a look at playlist: https://www./u1JCV3HNVwMPLSlkDq2rO1t6FCotFtvQEyURMThnQYKQD
First 2-3 videos should be enough to understand what you need to do here.
Basically you need to create a simple BP function in your C++ BP function library. In the header file you’d declare function like :
UFUNCTION(BlueprintCallable, Category = "My - functions", meta = (DisplayName = "Get Sound Wave from Wave file", Keywords = "Get Sound Wave from Wave file"))
static USoundWave* GetSoundWaveFromWaveFile(const FString& filePath);
And in .cpp file you’d create a definition for the function - code form my previous message.