International students can apply for accommodation in university hostel, as soon as they get the admission letter. Studentenwerk of your university manages hostel accommodation and all the information about application process, rent, location of hostels, application form etc. are available on the website of Studentenwerk of your university. In some big cities international students may have to wait for 1 or more semesters to get accommodation in student hostel.
To open a bank account process, one has to usually get an appointment from the bank. Bank staff will also inform you what documents you are required to take with you, when you go for the appointment. It is very important to have a bank account opened as soon as possible so that the blocked amount could be transferred to your bank account.
Yes, it's extremely important and also mandatory to have health insurance for the enrollment at the university. Without health insurance the registration process at the university can’t be accomplished.
Yes, as a student you are allowed to work for 120 full days or 240 half days. However, the visa that is issued from home country may not allow you to work till you get your residence permit after arrival in Germany.