One of the things I found the most difficult when living abroad is to understand the bureaucracy in a foreign country and usually this is one of those things that you need to understand because it very much affects your live in different ways. There are some mandatory procedures that you cannot ignore, such as a resident permit. For some countries you need to have everything set before you come to Sweden. For others, Brazilians for example, you just receive beforehand an certification of visa and you need to go to the Migration agency once you arrive here (you have to make an appointment). There the collect you photo and fingerprints and in one week you have you resident permit card.
This card looks like a ID card but it does not work like one. You cannot use it to prove your identity (only to show you can reside in the country, for example when you travel and want to come back) so you still need to walk around with your passport. After you visa is regularized you can apply for a personnumber at the Tax Agency of you town.
A personnumber it is something like your civic registration in Sweden. To have a personnumber is the best thing, it is like you have your existence acknowledge in the country, many types of services ask for this number and you have much more possibilities once you have it. You can still do must things without one, but it is much easier with it. To have one you need to go to the Tax Agency and bring your passport, your resident permit card and a certification that you are a student at the university (which it is easy to get from the LiU’s student system). And that’s it. After you apply, in one week you have your personnumber. Students staying for less than one year don’t get a personnumber, but you will be fine once is a shorter period.
After you have a personnumber, another thing you can apply for is a Swedish ID. This is a good idea because, obviously, you’ll have a card that works like an ID and things like open a back account or using the health system becomes easier. It is at the same Tax Agency but for that you need to make an appointment in their website. Then, you take you resident permit, your passport and your personnumber there and in one week you have your ID. You also need to pay a fee of 400Kr, but I think it is worth it given how things will get simpler.