Display Posts by Author

Hello there!

I am currently customizing my theme-based website but am struggling with an issue I cannot seem to resolve. In Twentyseventeen or most standard WP themes, clicking on an author’s name will display all posts by that author (see e.g. http://2017.wordpress.net/2016/10/17/looking-for-local-artists/ – if you click on author “Needle & Hook” all posts by that author are displayed).

However, this is a function missing in the theme I am using and which I can’t restore (I have tried to insert various codes into php but with no success). Any ideas on how I can restore the function?

My website is http://easteuropeanfilmbulletin.com.

Thank You!