You can either walk there directly from the train station through the beautiful city center of Strasbourg (takes about 20-25 min), or you can take the tram A or D (both are equivalent for that trip) directly from the train station (the tram station is underground) to the stop « Porte de l'Hôpital » and walk from there (ca. 5 min).
Coming the hotel to the conference venue (IRMA)The easiest is simply to walk directly to the IRMA building (takes about 15 min). The exact address is