Plugin help

Why does not work? How to generate a chest on random coordinates? How to add items to this chest?

if($cmd->getName() == "event"){
if($sender->hasPermission("event.event")){
$x = rand(1,100);
$y = rand(80,100);
$z = rand(1,100);
$sender->getLevel()->setBlock(new Vector3($x, $y, $z), Block::get(54, 0));
$sender->getServer()->broadcastMessage("§f• §8[§cEvent§8]§7 Skrzynka z cennymi itemami została wygenerowana na: X: $x Y: $y Z: $z §f•");
}
else{
$sender->sendMessage("§f• §8[§cEvent§8]§7 Ta komenda jest tylko dla administracji! §f•");
}
}