Dolibarr is an opensource ERP/CRM. If you have installed it with Dolistock you will be able to access to your stock's product data, and save locally being able to check whether you have internet or not.
To connect to your Dolibarr you must set your connection url and set your username and password. Your connection url is the one you use to connect via web to your Dolibarr installation. The best way to know is check the index.php file (is the one that you see when you enter in Dolibarr) and take off from the last "/".
Also in your current Dolibarr installation you have to enable the REST API module that comes with the core installation.