Please check if your apache server meets the system requirements. In 99% of the cases you will only have to configure your htaccess file to start with Typemill.
If you run your website with HTTPS (recommended), or if you want to redirect www-URLs to non-www URLs, then please check the htaccess file in the root folder. There are several use cases already prepared, and you can simply uncomment them, if needed.
In some environments (like 1und1) you have to use an empty slash as the rewrite base. If you have any trouble (e.g. get a 500 error from the server), then please activate this line in your htaccess and try again:
# In some environements, an empty RewriteBase is required: RewriteBase /