Can't Access () all members

i’ve included “Engine/World.h” header file to use () and i am able to access GetFirstPlayerController()(one of its member) but i couldn’t access GetPawn()(member of GetFirstPlayerController())…intellisense shows no member available…pls tell me what files to include??.
#include “OpenDoor.h”
#include “GameFramework/Actor.h”
#include “Engine/World.h”

// Sets default values for this component's properties
UOpenDoor::UOpenDoor()
{
	// Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
	// off to improve performance if you don't need them.
	PrimaryComponentTick.bCanEverTick = true;

	// ...
}


// Called when the game starts
void UOpenDoor::BeginPlay()
{
	Super::BeginPlay();
	
	()->GetFirstPlayerController()
}

void UOpenDoor::OpenDoor()
{
	AActor*Owner = GetOwner();

	FRotator Rotation = FRotator(0.f, -60.f, 0.f);

	Owner->SetActorRotation(Rotation);
}


// Called every frame
void UOpenDoor::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);
	
	// If the ActorThatOpens is in the triggervolume
	// then open the door
	if (PressurePlate->IsOverlappingActor(ActorThatOpens))
	{
		OpenDoor();
	}

}

API refrence is your friend

Check what GetFirstPlayerController()

It is APlayerController and GetPawn is there so you need to include header file of this class, look on page of that class:

Go below and you will find header file there class is declared and you need to include, the path you need to include is the one after wither “Public” or “Classes” directory:

Runtime/Engine/Classes/GameFramework/PlayerController.h