From Tibutrina station take the train towards Viterbo or Bracciano which leaves every 15 minutes (with a Metro ticket or for 1 euro in tobacconists) to Cesano di Roma.
The stops are:

Roma Tiburtina (Metro B)-Roma Tuscolana (Metro A)-Roma Ostienze (Metro B)-Roma Trastevere-Roma S.Pietro-Quattro Venti-Valle Aurelia (Metro A)-Appiano-Balduina-Gemelli-Roma Monte Mario-Roma San Filippo Neri-Ottavia-Ipogeo Degli Ottavi-La Giustiniana-La Storta-Olgiata-Cesano di Roma

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From Fiumicino airport take the train to Trastevere station (8 €), then change and take the train (1 € every 15 min) towards Bracciano or Viterbo and get off at the Cesano stop in Rome)