How can I set up a "blog" area? I am very new to Drupal and Twig.

I've a custom Drupal theme I've built, but my client now wants a "blog" system as well. This includes the following features:


Show most recent article in a blurb on the home page
List out articles with pagination on an archive page
Assign categories and/or tags to articles which when visited list out articles similar to the main archive page
Show "posted on" date on article page


I've got the last item working just fine, but I can't find anything useful Googling around for the first three items.

I'm using Drupal 8 and twig templates if that makes a difference.
Everything you listed is super common, almost basic in Drupal projects. So you can find plenty of tutorials and introductory articles about how to do those features. 


You can create the latest article blurb Block using Views module (it's in D8 core), then place the Block in a theme region and adjust its visibility to only show on the front page
You can create "Archive" page using Views (pagination is also a feature in Views) 
Tag articles with the Taxonomy module (create a Vocabulary with terms inside, then add a Taxonomy reference field on Article Content type). There is a out-of-box View "Taxonomy term" that automatically creates pages for each term and lists the articles tagged with that term
Submitted by and on can also be controled through the interface by editing the Content type settings (you only need twig if you need to override the HTML output) 


So get yourself some Drupal Views and Taxonomy tutorials ;)