Selecting taxonomy term in article and showing all articles titles associated with this term
1) Create a View block, when you create it use Show: Content.

2) Under Advanced Contextual Filters add Has taxonomy term ID

3) Select provide default value Type: Taxonomy term ID from URL (this will automatically grabs the term from your node) If you want, you can limit the terms by vocab. 

Even if your tax term reference field is limited to 1, maybe you should set it up as if it was unlimited, in case your client later wants to allow more than 1 value.

Change the multiple-value handling option to the 2nd one, share any term.

Scroll down to MORE and check mark allow multiple values.



Click Apply, to save the settings.



Now you want to exclude the current Article (node) from the list. No point in showing the Article the visitor is already viewing/reading.

4) Add another contextual filter of ID

5) Provide default value Type: Content ID from url (automatically grabs the ID from your node).

6) Scroll all the way down, and click on MORE, and check mark Exclude. 



So your Advanced section should look like this:





To place the block in your article, there are several ways.

Go to admin/structure/block and click on Place Block, search for your View Block and click on Place Block. 

In the configuration, under Visibility settings, select Content Types and check mark your content type. 



Site Note: There are other ways to insert/place your view: 


Through a template file.
Using Panels and or Display Suite (Note: I am not 100% sure on this as I have not played much with these modules in D8, in D7 I know you can).