The Haunted Carriage follows its established route

Like many of Diablo Immortal's themed events it isn't possible to walk right up to the Haunted Diablo 4 Gold Carriage whenever the mood gets you. In fact, the window for participating in this event is quite tiny.

The Haunted Carriage is spawned within Ashworld Manor every Tuesday and Saturday between 12 pm., 8:30 pm, and 10 pm (based on your server's local time). It's recommended to arrive at at least 10-15 minutes early to ensure that you don't miss your shot it's more of a general advice than a strict requirement. In any event, as it's in the nearby vicinity of the carriage, you'll be shown an on-screen announcement informing you that the event is about to begin and asks whether you'd like participate.

When the Haunted Carriage is born it'll take a route that is pre-determined to reach its final destination. It is also possible to simply meet the Haunted Carriage when it's en way to its destination (or just be patient until it arrives at the end of the road), but you're really more likely to follow the carriage in its journey rather than just taking part in a limited portion of the festival. For reference, here's the map of the path the carriage takes through the area (map taken from Wowhead):Once you've tracked down the carriage, it's time to participate in the event in the event.

When the Haunted Carriage follows its established route, it will occasionally be attacked by guards. Guards' positions buy cheap Diablo IV Gold are shown by skulls in this map. There may be a small deviation on the exact location, they spawn, but they are usually found in the same general area.