Making RewriteRule display content

I’m trying to learn Apache but a lot of the documentation and tutorials assume more knowledge than a newbie like me has.

I have a directory structure that looks like this:
mrtest\gstyle\mini\cooper

In the directory mrtest I have a .htaccess file that contains:
RewriteEngine On
RewriteRule ^go$ gstyle/mini/cooper/$1 [L]

In the directory mrtest\gstyle\mini\cooper have the following files:
index.html
buttons.png

So when I go to mrtest7/go, I am correctly served the index.html content buttttt

When I go to mrtest7/go/index.html I get:
Not Found
The requested URL /mrtest7/go/index.html was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

When I go to mrtest7/go/buttons.png I get the same error.

I’ve got so many tabs of documentation open and have read every one but I’m still confused as to how this works. Any guidance would be greatly appreciated.