Edit fluidity3c to a default theme

Hi,

how can i make the theme fluidity3c-10
https://themes.wordpress.net/columns/3-columns/45/fluidity3c-10/
to a “default” theme?

In this theme is not the 404.php (disable) if i type any adress after the blog-url, i go to the startpage of my blog.

and some other files are make in the other files… pleas test the theme self to can help me.

i will:
– add the error404-page
i have testet to copy
<?php /* If this is a 404 page */ if (is_404()) { ?>
in the header.php (note: in this theme is not as default the information in the index.php! the info about the 404-page is on the header.php… ) and the default 404.php-file – and not works.

– the page.php and single.php as a default wordpress-theme to edit the site and add option (print the site-option…).

Note: i have today contact the designer of the theme. but i will now know how i use the default php-files.
And i run at this time wordpress on localhost, i can’t get you a url.