As you have copied pasted the code from demo, please change the url in dataModel and ensure that they are pointing to the controllers correctly.
var dataModel = {
location: "remote",
sorting: "local",
dataType: "JSON",
method: "POST",
sortIndx: "OrderID",
sortDir: "up",
url: "/orders/get",
//url: "/pro/orders.php",//for PHP
getData: function (dataJSON) {
return { data: dataJSON.data };
}
}
And better to start from a simple demo ( rather than remote filtering demo ) if it's your first one.