Custom Template

I am using web Seo theme and have done a lot of customization for client
Now the client wants to redirect the user to a page where we can display content of the property listing and everything is pretty much completed and I have done coding on a local server where content will be changed based on the property id
Link of the website in the related URL field

I need to know how to develop a custom template within the theme that changes content dynamically. The template has been completed but unable to add it within a theme

I have google and found this article relevant:
https://developer.ww.wp.xz.cn/themes/template-files-section/page-template-files/

The page I need help with: [log in to see the link]