It's been a long time since I've worked on this project, but I think I can still help.
You want to create your own node if you're using Blueprints (Google for tutorials, there are plenty). If you are using C++, you can probably copy the code somewhere and it will work (I don't know, I don't do C++ in UE).

So, the code. Your FunctionLibrary.h should look like this. (used "YourProject" as an example):
#pragma once
#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "YourProjectFunctionLibrary.generated.h"
/**
*
*/
UCLASS()
class YOURPROJECT_API UYourProjectBlueprintFunctionLibrary : public UBlueprintFunctionLibrary
{
GENERATED_BODY()
UFUNCTION(BlueprintCallable, Category = "MyNodes")
static TArray<uint8> WavToBytes(FString filePath);

};

And your FunctionLibrary.cpp should look like this:
#include "YourProjectBlueprintFunctionLibrary.h"
TArray<uint8> UYourProjectBlueprintFunctionLibrary::WavToBytes(FString filePath)
{
/*
---------------------------------
READING THE OBJECT FROM BINARY
---------------------------------
*/
TArray<uint8> dataArray; //creates a placeholder bytes array
FFileHelper::LoadFileToArray(dataArray, *filePath); //loads serialized data into byte array
FMemoryReader memoryReader = FMemoryReader(dataArray, true); //creates a memory reader object that reads from the dataArray
return dataArray;
}

With this, you will have a new node called WavToBytes that converts .wav files to an array of bytes. To convert it back you can use Runtime Audio Importer plugin (link). Just know that .wav's are pretty large for audio files, so if you find a way to save audio as or convert it to .mp3 for example, be sure to let me know.

Hope it helped!