Extract gween.tgz to the document-root of your webserver.
Copy config.inc.php.dist to config.inc.php and change it according your needs.
Give the webserver full right on the cache directory.
It is recomended to define an rewrite rule for gween so it can be access by web without index.php and non-template files can be used in the component-direcotry.
RewriteEngine on RewriteRule ^($|.*\.comp|.*/)($|\?) index.php RewriteRule index.php - [L] RewriteRule (.*) COMP_PATH/$1
Set COMP_PATH to your compont path
Optionally you may define an URI rewrite rule that redirect webserver queries to gween, so gween can be used without specifying the path to gween (e.g. http://somehost/php/gween/index.php/some_component.comp could become http://somehost/gween/some_component.comp).
Put following directives in the configuration of then gween direcotry or in an .htacces file
RewriteEngine on RewriteRule ^($|.*\.comp|.*/)($|\?) index.php RewriteRule index.php - [L] RewriteRule comp/ - [L] RewriteRule (.*) comp/$1