I need help postgame (SPOILER)

So I went to Holon region, I beat Maple, I captured Regigigas, Delta Regice (Water) and Delta Registeel (fire), but I CANT find Delta Regirock, and I dont know what to do next? where do I go? I mean I really dont care that much about the Delta Regirock (but it could be nice to have), I just wanna know whats next? whats the next step, whats the next story? Am I done with Holon? should I just leave that place?

Please help :frowning:

up, still dont know what to do there, I still cant find regirock delta and I feel like theres still Im missing there

Delta regirock is in the desert on a small platform that requires rock climb. Behind 2 rocks is a small patch of quicksand, just walk on it and you fall into itโ€™s cave.