Ersten Schritte sind schwer

// .h
// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.


#pragma once


#include "GameFramework/Actor.h"
#include "Countdown.generated.h"


UCLASS()
class HOWTO_VTE_API ACountdown : public AActor
{
    GENERATED_BODY()


public: 
    // Sets default values for this actor's properties
    ACountdown();


    // Called when the game starts or when spawned
    virtual void BeginPlay() override;


    // Called every frame
    virtual void Tick( float DeltaSeconds ) override;


    //How long, in seconds, the countdown will run
    int32 CountdownTime;


    UTextRenderComponent* CountdownText;


    void UpdateTimerDisplay();


    void AdvanceTimer();


    void CountdownHasFinished();


    FTimerHandle CountdownTimerHandle;
};


//.cpp
// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.


#include "HowTo_VTE.h"
#include "Countdown.h"


// Sets default values
ACountdown::ACountdown()
{
    // Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    PrimaryActorTick.bCanEverTick = false;


    CountdownText = CreateDefaultSubobject<UTextRenderComponent>(TEXT("CountdownNumber"));
    CountdownText->SetHorizontalAlignment(EHTA_Center);
    CountdownText->SetWorldSize(150.0f);
    RootComponent = CountdownText;


    CountdownTime = 3;
}


// Called when the game starts or when spawned
void ACountdown::BeginPlay()
{
    Super::BeginPlay();


    UpdateTimerDisplay();
    GetWorldTimerManager().SetTimer(CountdownTimerHandle, this, &ACountdown::AdvanceTimer, 1.0f, true);
}


// Called every frame
void ACountdown::Tick( float DeltaTime )
{
    Super::Tick( DeltaTime );


}


void ACountdown::UpdateTimerDisplay()
{
    CountdownText->SetText(FString::FromInt(FMath::Max(CountdownTime, 0)));
}


void ACountdown::AdvanceTimer()
{
    --CountdownTime;
    UpdateTimerDisplay();
    if (CountdownTime < 1)
    {
        // We're done counting down, so stop running the timer.
        GetWorldTimerManager().ClearTimer(CountdownTimerHandle);
        //Perform any special actions we want to do when the timer ends.
        CountdownHasFinished();
    }
}


void ACountdown::CountdownHasFinished()
{
    //Change to a special readout
    CountdownText->SetText(TEXT("GO!"));
}