Adddynamic declaration confusing me

Hello,(and sorry for the other post on this function)
I try to make a collactable item in c++ and i can’t get the function to work.
I try to declare it but i don’t know how it work :frowning:

this is my Item.cpp




#include "Components/BoxComponent.h"
#include "Item.h"
#include "Engine.h"

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

    TBox = CreateDefaultSubobject<UBoxComponent>(TEXT("Box"));
    TBox->SetGenerateOverlapEvents = true;
    TBox->OnComponentBeginOverlap.AddDynamic(this, &AItem::TriggerEnter);
    TBox->OnComponentEndOverlap.AddDynamic(this, &AItem::TriggerExit);

    RootComponent = TBox;

    SM_TBox = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Box Mesh"));
    SM_TBox->AttachTo(RootComponent);

}


void AItem::GetPlayer(AActor* Player)
{
    MyPLayerController = Cast<AItemMenuCharacter>(Player);
}

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

}

AItem::DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FActorBeginOverlapSignature, AActor *, MyPLayerController, AActor *, OtherActor)
{
}

void AItem::Pickup()
{
    MyPLayerController->Inventory.Add(*ItemName);
    GEngine->AddOnScreenDebugMessage(-1, 5.f , FColor::Green, TEXT("You Picked the item up !"));
    Destroy();
}

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

    if (MyPLayerController != NULL) //Nullcheck player controller
    {
        if (MyPLayerController->bIsPickingUp && bItemIsWithinRange)
        {
            Pickup();
        }
    }
}

void AItem::TriggerEnter(class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult & SweepResult)
{
    bItemIsWithinRange = true;
    GEngine->AddOnScreenDebugMessage(1, 5.f, FColor::Green, FString::Printf(TEXT("Press E to Pickup %s"), *ItemName));
    GetPlayer(OtherActor);
}

void AItem::TriggerExit(class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex)
{
    bItemIsWithinRange = false;
}



ad my item.h


// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "ItemMenuCharacter.h"
#include "Item.generated.h"

UCLASS()
class ITEMMENU_API AItem : public AActor
{
    GENERATED_BODY()

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

    UShapeComponent* TBox;


    UPROPERTY(editAnywhere)
        UStaticMeshComponent* SM_TBox;

    AItemMenuCharacter* MyPLayerController;
    DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FActorBeginOverlapSignature, AActor*, MyPLayerController, AActor*, OtherActor);

    UPROPERTY(editAnywhere)
        FString ItemName = FString(TEXT(""));

    void Pickup();

    void GetPlayer(AActor* Player);

    bool bItemIsWithinRange = false;

    UFUNCTION()
        void TriggerEnter(class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult & SweepResult);

    UFUNCTION()
        void TriggerExit(class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);



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

public:    
    // Called every frame
    virtual void Tick(float DeltaTime) override;

};



thank you