How to execute my custom C++ Actor (procedural level generator) at runtime

Thank you Master Kyp, BeginPlay inside the GameMode did the trick. This is the code I added inside my TestGameMode.h and TestGameMode.cpp, just for posterity:

//h

public:
virtual void BeginPlay() override;

//cpp

void ATestGameMode::BeginPlay()
{
	Super::BeginPlay();

	UWorld* const World = GetWorld();
	if (World)
	{
		World->SpawnActor<AMapGenerator>(AMapGenerator::StaticClass());
	}    
}

And thanks for the tip on the bonus question too. If I’ll need more help with it I’ll post a specific question. Bye!