How to edit latest posts blog page format

Hi There

Sorry if this is a stupid question but i can’t work out how to do this

I want my latest posts blog page layout to look like the Blog Medium Sidebar Right demo page as seen here:

Medium Sidebar Right

I’ve set my hmepage to display my latest posts but they currently display the feature image excessively large like this:
https://imgur.com/a/v9LXJs3

How do i go about changing this?

Thanks

Ticket