This shows how an Asset can be loaded from C++. Here a Plane and a corresponding Material is loaded

UnrealAssetLoading.cpp

template <typename T>
bool LoadAsset(const FString& Path, T* & Result)
{
	ConstructorHelpers::FObjectFinder<T> Loader(*Path);
	Result = Loader.Object;
	if (!Loader.Succeeded()) UE_LOG(LogTemp, Error, TEXT("Could not find %s. Have you renamed it?"), *Path);
	return Loader.Succeeded();
}

AMyClass::AMyClass()
{
	UStaticMesh* PlaneMesh = nullptr;
	UMaterial* StripesMaterial = nullptr;
	
	// Loading of Blueprint/Meshes/Materials
	// In this case, the plugin contains a StaticMesh named "Plane" and a material named "Stripes"
	LoadAsset("/MyPlugin/Plane", PlaneMesh);
	LoadAsset("/MyPlugin/Stripes", StripesMaterial);
	
	// Creation of sub-components
	USceneComponent* Root = CreateDefaultSubobject<USceneComponent>("DefaultSceneRoot");
	SetRootComponent(Root);
	
	//Declare Result in Header file
	Result = CreateDefaultSubobject<UStaticMeshComponent>("MyVeryOwnPlane");
	Result->SetStaticMesh(PlaneMesh);
	Result->SetupAttachment(Root);
}

// Bind Materials in PostInitializeComponents, else it can have weird side effects
void AMyClass::PostInitializeComponents()
{
	Super::PostInitializeComponents();
	
	Result->SetMaterial(0, StripesMaterial);
	
	//Can be dynamic material as well
	//UMaterialInstanceDynamic* MyDynamicMaterial = UMaterialInstanceDynamic::Create(StripesMaterial, Result);
	//Result->SetMaterial(0, MyDynamicMaterial);
}