HTML fixed navigation bar

Hi, everyone, I am pretty new to coding, Im taking a class where the teacher wants a fixed nav bar using the iframe element so the landing page doesn’t change but the webpages are displayed. I hope I explained the issue properly. My page keeps displaying the iframe on the side which is not correct.

Well, I think you are facing issue in fixing navigation bar, here is the simple HTML code that you have to check with your code:

<!DOCTYPE html>
<html lang="en">
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Your Webpage Title</title>
        /* Add CSS styles for your fixed navigation bar */
        /* For example, you can make it fixed at the top, set background color, etc. */
        /* Add any other necessary styles here */
    <!-- Create the fixed navigation bar -->
        <!-- Add your navigation items here, such as links to different webpages -->
        <!-- For example: <a href="page1.html">Page 1</a> -->

    <!-- Create the iframe to display the content -->
    <iframe src="landing.html" frameborder="0"></iframe>

Well, if the problem will not be solved after this, then please post your complete code here.