You need to have paid plan to use Auto sync feature.
To enable Auto sync in web interface go to Details/Auto sync and select sync time, sync period and access points to connect to Internet. Please be sure that your phone is online so don't forget to start Agent before.
Also you can setup Auto sync on the phone. Start Agent, select Options/ Acc. points to setup access points to connect to Internet. Then select Options/ Sync settings to setup sync time and sync period.