Need to add written and photo content to bottom of existing archive pages

Have a WordPress site that is not letting me post content below the group of product thumbnails already existing on the category pages. (NOTE: These pages are archive pages in WordPress).

The additional content I want to post is around 900 words plus a full width photo. There are five such pages, each to get its own 500 words of content. Here are the pages that need the content added under the property thumbnail group.

https://pacificislandsreservations.com/property_group/diamond-head/
https://pacificislandsreservations.com/property_group/kailua/
https://pacificislandsreservations.com/property_group/lanikai/
https://pacificislandsreservations.com/property_group/northshore/
https://pacificislandsreservations.com/property_group/big-island/

Company
Spiritual Quest
Job Type
Project
Location
Los Angeles, CA, USA
Budget
Not much
How to Apply
Via email