From Resecentrum (the main bus terminal) or the central station (the train station) in Borås, which are located just next to eachother, the easiest way to get to your accommodation with a lot of luggage is by taking a taxi. There are taxis waiting outside the terminal buildings.
If you rather take the bus, most local buses depart from the bus stop Södra Torget, a 5-10 minutes walk through the city center. The easiest way to get there is by using Google Maps (external link). It also tells you which bus to take to your destination.
It is important to arrange when and where to pick up your keys, especially if you are arriving outside office hours (9am - 4pm). Students that rent from Bostäder i Borås can contact them to arrange to pick up the keys at Scandic hotel Plaza, next door to the University, but it needs to be arranged at least 7 days in advanced.