You need to learn markdown if you have or contribute to repositories on websites like GitHub, or for forums and learning sites like freeCodeCamp. Specifically, you need it for creating and editing README and other documentation files. In this Markdown cheat sheet, I will show you the basic Markdown syntax . . .
I prefer to do as much as I can in WordPress without using a plugin. A simple thing is to write a WordPress custom query to display the 3 most recent posts in a category or other criteria. I show the code I used to generate the 3 most recent posts using 2 different custom queries.