How do I use Caching or use a .htaccess file in ghost?

If I google “Ghost blog .htaccess” or “ghost blog expiration headers” not much seems to happen.

This document doesn’t seem to explain much on how to configure caching either: https://ghost.org/docs/concepts/config/#caching

There is a link (presumably to a page on caching) but it doesn’t work.

Ghost uses Nginx primarily so you can use Nginx Expiration rules for ghost.
.htaccess is used by apache

You can get more information about caching with Nginx in below link