Question about EZVIZ C3X

I can't find a way to load a custom audio alert. I wrote to ezviz and this is their reply: "Please go to the camera settings page - alarm notification - select mode - custom sound. I wrote to ezviz and this is their reply: "Please access the camera settings page - alarm notification - select mode - custom sound", only I can't find alarm notification let alone select the mode. Can you help me?