The following rules export is an example that translates all articles which are not already german or undefined to german using translator called test_translator (Microsoft in this case, but any translator that supports automated checkout should work).

{ "rules_auto_translate_with_microsoft" : {
    "LABEL" : "Auto-Translate with Microsoft to German",
    "PLUGIN" : "reaction rule",
    "REQUIRES" : [ "rules", "tmgmt" ],
    "ON" : [ "node_insert", "node_update" ],
    "IF" : [
      { "node_is_of_type" : { "node" : [ "node" ], "type" : { "value" : { "article" : "article" } } } },
      { "NOT data_is" : {
          "data" : [ "node:language" ],
          "op" : "IN",
          "value" : { "value" : { "und" : "und", "de" : "de" } }
        }
      }
    ],
    "DO" : [
      { "tmgmt_rules_create_job" : {
          "USING" : { "source_language" : [ "node:language" ] },
          "PROVIDE" : { "job" : { "job" : "Job" } }
        }
      },
      { "tmgmt_rules_job_add_item" : {
          "job" : [ "job" ],
          "plugin" : "entity",
          "item_type" : "node",
          "item_id" : [ "node:nid" ]
        }
      },
      { "data_set" : { "data" : [ "job:target-language" ], "value" : "de" } },
      { "data_set" : { "data" : [ "job:translator" ], "value" : "test_translator" } },
      { "tmgmt_rules_job_checkout" : { "job" : [ "job" ] } }
    ]
  }
}