It is possible to either access the files diretly using the webdav protocol or installing a desktop sync client.
It you want to use a synchronized desktop client, we recommend using the Owncloud client, http://owncloud.org/install/#desktop/. It is available for most operating systems.
To directly connect to OPI, connect to a network drive using the webdav protocol.
For linux the url is davs://opiname.op-i.me/oc/remote.php/webdav.
For windows this requires that you install the OPI CA in order to connect securly to OPI. A description on how to do this is coming ….