Google Adsense within post (automatic)

Im looking to integrate a small google adsense ad into my posts (maybe 300×250 max in size) but I dont want to have to manually insert it every time since some of my writers are not too savvy with WP. I saw an example here (https://www.lancelhoff.com/hdmi-sound-from-laptop-to-tv/) which I would like to follow. This is what my code looks like now. How can I change it to get the ad to left justify within the first paragraph.

<h1><?php the_title(); ?></h1>
<h2>by <?php the_author_posts_link(); ?> on <?php the_time('F jS Y'); ?> at <?php the_time('g:iA'); ?></h2>
<?php the_content('Read the full post &raquo;');?>
<div style="clear:both;"></div>

This is a sample page of mine. (https://www.motorthusiast.com/333/austin-us-formula-1-track-design-revealed/)