สอบถามหน่อยครับ จะ insert ค่าใน textbox ลง checkbox ได้อย่างไรบ้างครับ

<?php
if(isset($_POST['id_manager'])){
  foreach($_POST['staff'] as $staff){
     // update tbname set approve=id_manager where staff = $staff
  }
}
?>
<form>
Manager   <input name="id_manager">
<input type="checbox" name="staff" value="staff1"> Staff 1
<input type="checbox" name="staff" value="staff2"> Staff 2
<button>Save</button>
</form>

  //TEST
/*
  $sql = "UPDATE ReqUser SET LvApprove = ?, Authentication = ?, Status = ? WHERE EmpUserID = ? ";
  $params = array($_POST["txtManager"], $_POST["txtAuthen"], $_POST["txtStatus"], $_POST["staff"]);
  $stmt = sqlsrv_query( $conn, $sql, $params);
  if( $stmt === false ) {
    echo "<script type=text/javascript>alert('Unsuccessful error!');javascript:history.back(1);</script>";
    exit();
  }
  else
  {
    echo "<script type=text/javascript>alert('Successfully updated');javascript:history.back(1);</script>";
    exit();
  }
*/


if(isset($_POST['txtManager'])){

 $txtManager = $_POST['txtManager']; //textbox

  foreach($_POST['staff'] as $staff){ //checkbox

    $sql = "UPDATE ReqUser SET LvApprove = ($txtManager), Authentication = ($txtAuthen), Status = ($txtStatus) WHERE EmpUserID = ($staff) ";
    $stmt = sqlsrv_query( $conn, $sql );
  }
}

foreach($_POST['staff'] as $staff){ // กำหนดคีย์อ้างอิง
     // update tbname set approve=$manager_id, authen=$authen[$staff] where staff = $staff
}