I am from India and I have been offered postdoc in University of Basel, Switzerland for three years. The University HR has asked to check the Swiss Embassy homepage to apply for visa D for training. In the embassy page (https://www.eda.admin.ch/countries/india/en/home/visa/entry-ch/work-permits/documents-work-permits.html), I have been asked to fill a visa application and give 2 passport photos, authorization letter, passport. No flight tickets have to be booked to apply for visa D?. How is the visa application processed here in India for Visa D?