How do we customize the layout of the listings page?

We’re not using the built-in theme but our own theme. What files do we edit properly to customize the look and feel of the list of members by category /listings-category/general/ and the layout of the individual member /listing/membername. I have found the file loop-taxonomy.php in the plugins/directory/core/ui-front/general and changes there are reflected on the page but I wanted to make sure I edited the correct files.

Also is there a way to change the taxonomy/custom posts name from listing/listings/listings-category to something like member/members/members-category?

TIA

Rob