Get yourself familiar with visa, entry and residence requirements for AUSTRIA. Check this FAQs on visa as well as information provided in the OeAD database. The EM CDE Student Handbook provides you with guidance on steps-to-do for pre-arrival arrangements and first things to do upon arrival in Salzburg, at the University of Salzburg (PLUS).
EU/EEA nationals need neither a visa nor a residence title. They, however, have to register with the authority in charge of residence within three months of entering Austria; see https://studyinaustria.at/en/living/entry/.