Activating Items

[HotbarComponent] → UseHotbarSlot
   Slot Index: 0
   Return: Success (true/false)

bool bUsed = HotbarComponent->UseHotbarSlot(0);

IA_Hotbar1 (Triggered)
   ↓
[HotbarComponent] → UseHotbarSlot
   Slot Index: 0

void AMyCharacter::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
    PlayerInputComponent->BindAction("Hotbar1", IE_Pressed, this, &AMyCharacter::UseHotbarSlot1);
    PlayerInputComponent->BindAction("Hotbar2", IE_Pressed, this, &AMyCharacter::UseHotbarSlot2);
    // ...
}

void AMyCharacter::UseHotbarSlot1()
{
    HotbarComponent->UseHotbarSlot(0);
}