how to change existing form

Hi I have some existing web page
I need to duplicate the page and then to change the form to this form :
inside

<head>:
<link rel="stylesheet" 
  target="_blank" rel="nofollow" href="https://trafficbalance.io/static/css/sdk/sdk.css">

 before </body> closes:
  <script src="https://trafficbalance.io/static/js/lib/jquery.min.js">
</script> if jQuery is already in page, no need to add this line.
 <script src="https://trafficbalance.io/static/js/sdk/all.min.js"></script>
 <script>
   $(function() {
   tbsdk.init({
container: '#cont',
 pipe: '0rSX2a2',
 campaign: '13',
 sub_campaign: '30DayChange',
  password_required: true,
  extra_data: {
   subAffiliateId: "30DayChange"
  }
  });
 });
</script>

and to put this div instead of the original form:

  <div id=“cont”></div>

I don’t understand what does it mean to change the existing from to this form:

<link rel=”stylesheet”
target=”_blank” rel=”nofollow” href=”https://trafficbalance.io/static/css/sdk/sdk.css”>
this is an css file, any one can please explain me what does it mean?
thanks!

Your question isn’t very clear, but i think i got it.
There’s a CSS rule called “cascade”, wich means that more specific styles overrite the generic ones, so, you can specify a style to your <div> element by adding

<style>
    div{
        style propeperties
    }
</style>

or

<style>
    #elementId{
        style propeperties
    }
</style>