Thanks anyway. In case anyone else is trying to figure this out. I figured it out on my own, after reading many, many pages of jibberish.
the line of code to do this is
<?php $posts = get_posts('category=4&numberposts=3&order=DSC&orderby=post_date');
If you need to figure out the numbers of you categories, go to your site, and click on each of them. WordPress seams to randomly generate these numbers, so they are not sequential. Although a few of mine are.
You can see this code in action at https://soflanetworking.com/west_palm_beach/
The main page shows only “Office Tips”, each sub page, shows topics relevant to the page. For example the https://soflanetworking.com/west_palm_beach/computer_repair.php page only shows blog post related to computer repair.