If it is a full backup, you can simply put the files wherever it seems appropriate, and import the database.
You will need to modify four files: config.core.php, connectors/config.core.php, manager/config.core.php - these are to specify the path to the MODX core. This should be the absolute file path according to the server's file system. For example,
define('MODX_CORE_PATH', '/Applications/MAMP/htdocs/templates.modx/core/');
I have this installation in a subdirectory named "templates.modx" on my localhost, using MAMP. If it were in the web root, it would be
define('MODX_CORE_PATH', '/Applications/MAMP/htdocs/core/');
The core/config/config.inc.php file needs to be edited extensively to correct the database connection information as well as all of the paths. One example of part of these settings is
if (!defined('MODX_MANAGER_PATH')) {
$modx_manager_path= '/Applications/MAMP/htdocs/templates.modx/manager/';
$modx_manager_url= '/templates.modx/manager/';
define('MODX_MANAGER_PATH', $modx_manager_path);
define('MODX_MANAGER_URL', $modx_manager_url);
}
You especially need to take care to not miss the $database_dsn line, one of mine looks like this
$database_dsn = 'mysql:host=localhost;dbname=templates;charset=utf8';
and also it's easy to miss the paths for the assets directory, they are defined near the bottom of the config.inc.php file.