I have found how to start the app "SmartShare" in my LG TV, using the command ssap://com.webos.applicationManager/launch, and the param {id: 'com.webos.app.smartshare'}.
I'd like to start the app pointing to a DLNA server in my network, and, if possible, pointing to a path there, however, I've not been able to find documentation for that specific app.