Header Banner for single pages

Hello,
I am really new to ‘wordpress theme modification’ and have little or no knowledge of PHP coding. I have a site on which I am using ‘argoniod’ theme.

link: https://www.paddsolutions.com/wpmag/argonoid/

The theme is fine, only that I need multiple banner in the site I am designing, insted of one banner the theme is using.

The theme is using the following code in header.php

<div class="box box-masthead">
				<?php $tag = (is_home()) ? 'h1' : 'p'; ?>
				<<?php echo $tag; ?> class="title"><a href="<?php echo get_option('home'); ?>"><?php bloginfo('name'); ?></a></<?php echo $tag; ?>>
				<p class="description"><?php bloginfo('description'); ?></p>
			</div>

			<div class="box box-ads">
				<h3>Advertisement</h3>
				<div class="interior">
					<?php padd_theme_widget_banner(); ?>
				</div>
			</div>

I have modified the code a bit to display four banners linked to sub-pages of wordpress. The above code looks like this:

<div class="box box-masthead">

                        <?php $tag = (is_home())? 'h1' : 'p';?>
		        <<?php echo $tag; ?> class="title"><a href="<?php echo get_option('home'); ?>"><?php bloginfo('name'); ?></a></<?php echo $tag; ?>

			<p class="description"><?php bloginfo('description'); ?></p>

			</div>
			<div class="box box-ads">
				<h3>Advertisement</h3>
				<div class="interior">

<ul>
<li><a href="https://www.tanvirmorshed.com/indigorestaurant/about/conference-and-private-party/"><img src="Conference and Private Party.png" alt="Indigo Conference and Party Room for hire" width="160" height="80" /></a></li>
<li><a href="https://www.tanvirmorshed.com/indigorestaurant/about/Presentation-room-for-hire/"><img src="Presentation Room.png" alt="Indigo Presentation Room for hire" width="160" height="80" /></a></li>
<li><a href="https://www.tanvirmorshed.com/indigorestaurant/about/indigo-in-a-hurry/"><img src="Indigo In a hurry.png" alt="Indigo in a hurry" width="160" height="80" /></a></li>
<li><a href="https://www.tanvirmorshed.com/indigorestaurant/menus/indigo-lunch-platter/"><img src="Indigo Lunch Platter.png" alt="Indigo Lunch Platter" width="160" height="80" /></a></li>
</ul>

				</div>
			</div>

The problem is the four banners is not showing up in ‘single pages of the site’. I am just wondering how can I show the four banners in ‘single pages’ as well as ‘home page’.

Many thanks in advance for the help.