can someone help please

i am new to wordpress , i installed wordpress in directory
( wordpress ), under the link
http://www.adv-bh.com/wordpress
i need to make the blog at http://www.adv-bh.com
but could not manage following steps of help files
which says :

3.Change the following and save the file.
Change the line that says:
require(‘./wp-blog-header.php’);
to the following, using your directory name for the WordPress core files:
require(‘./wordpress/wp-blog-header.php’);
4.Login to the new location. It might now be http://example.com/wordpress/wp-admin/
If you have set up Permalinks, go to the Permalinks panel and update your Permalink structure. WordPress will automatically update your .htaccess file if it has the appropriate file permissions. If WordPress can’t write to your .htaccess file, it will display the new rewrite rules to you, which you should manually copy into your .htaccess file (in the same directory as the main index.php file.)

can someone help please in clear way
or tell me how to write the address correctly
based on my site address
specially in steps three and four ?

also i cannot find .htaccess files in wordpress directory?
thanks in advance