How do I set value for Jquery Datatables filter?

I have my input and button

<input id="gridSearch" type="text" /> <button id="filter" class="btn btn-default">Buscar</button>

and my table

$.fn.dataTable.ext.legacy.ajax = true;
var grid = $("#gridCustomer").DataTable({
    "language": {
        "sProcessing": '<img src="/Scripts/loadingBgBlack.GIF" /> Loading...'
    },
    "bFilter": false,
    "bLengthChange": false,
    "processing": true,
    "serverSide": true

How do I set the value to filter on the grid?

$('#filter').click(function (e) {

    var searchValue = $("#gridSearch").val();

});

Why did I do this?

Why do I want to put the input in another position, and I want it to search only when you click on "Search".

Then I removed what comes standard, using "bFilter": false and manually adding my own input with button