Do you want to install WordPress on your server but want to keep your root directory clean?
The easiest way to do this is just to install the files for WordPress into a subdirectory, change the site address to the root, and then copy the index.php up to the root, and then edit one line to reference the new WordPress subdirectory.
require( dirname( __FILE__ ) . '/wp-blog-header.php' );
require( dirname( __FILE__ ) . '/subdirectory/wp-blog-header.php' );
For more info, check out the official WordPress documentation https://codex.wordpress.org/Giving_WordPress_Its_Own_Directory