Post Thumbnals on Front Page

Hi, using 2017 theme. I can’t seem to add a thumbnail to a post on the front page. I get some text then the read more link and then on the post page the whole post text with any featured images I add. But I want a thumb option along with the abbreviated on the front page. I’ve tried recommended modifications to my child theme but there are problems with each mod attempt.

Is there a way? Thanks.