The Manual
« Section 3 »
3.1 Configuration
After you have installed GlotPress, the only additional step you must do (or have done previously) is to configure your permalinks in WordPress. GlotPress requires a permalink setting other than “Plain”.
In addition, if you do not want to access GlotPress through the default path (\glotpress) you can change this by adding the following line to your wp-config.php file:
define('GP_URL_BASE', '<your-path-here>');
You can replace with anything you like but be careful to select something that will not cause a collision with another page or post.
If you wish to have GlotPress accessed from the root of your WordPress installation, you can use:
define('GP_URL_BASE', '/');
GlotPress comes with a default set of templates (kind of like a WordPress theme) for generating it’s pages. You can create your own custom templates however you CANNOT store them in the plugin directory or they will be overwritten upon the next GlotPress upgrade you install. Instead, create a directory somewhere else in your site and store the templates there, then add the following line to your wp-config.php file:
define( 'GP_TMPL_PATH', '/var/www/example.org/gp-templates' );