On your arrival, please, contact within two days the INFN Director's Office or the Summer Exchange Program Secretariat from Monday to Friday (9.00-12.00/14.30-16.00). These offices will help you to communicate your arrival to the Police-headquarters, sending them your passport copy and visa.

You don't need to request a "Residence Permit" (permesso di soggiorno).

You then have to contact the INFN Administration Office which will provide you a standard scheme for health insurance in case of emergency.