BSN
In terms of administration, the main thing you need to know is that you have to book an appointment as soon as possible at the townhall to get your BSN. In a few words, the BSN is the citizen service number. It is unique to each citizen in Groningen and it is allocated to everyone registered in the BRP (Personal Records Database). If you are planning to live in the Netherlands for more than 4 months, it is obligatory to request it by registering at the Gemeente Groningen, which is basically the city hall. The BSN is required for a lot of administrative paperwork such as opening a bank account, or paying taxes. Therefore, if you intend to work here, I would greatly advise you to book an appointment as early as possible because otherwise, all companies will give priority to students who already made the administrative procedures and received it. When you move out of the country, you need again to get in touch with the Gemeente to let them know that you will not be a Groningen citizen anymore. The following link explains all you need to know about this topic before moving to the Netherlands, and you can as well find the link towards the form to fill to get a booking at Gemeente.
Bank card
It is not necessary to have a Dutch bank card. Indeed, not having one and working in a company are not incompatible. With only an IBAN, I can easily receive money transfers from my employer and therefore it was not obligatory for me to go through the process of obtaining a Dutch card.
Most of the stores unfortunately do not accept the VISA card because otherwise, they have to pay a big amount of taxes to the government which makes their business non profitable. In the supermarkets, Albert Heign and Jumbo, to quote only the most popular ones, when you do not own a Dutch card, you absolutely need to have cash on you. It is therefore pretty annoying and inconvenient but it is really doable with a bit of organization. You have to go to a cash dispenser in order to have enough cash to pay your weekly expenses including grocery shopping. There are a few of them in the city and the ones I usually go to are ING machines located in the two Albert Heign closest to the center, i.e. the first one is near Grote Markt and the other one close to Vistmarkt. I have a tendency to be particularly disorganized when it comes to administrative documents. However, I would still definitely advise a new student in town to launch the procedures to get a Dutch card because having one is a life facilitator. Indeed, I usually need to ask my friends to pay for me whether the payment has to be made online, though a Dutch website for example or in a physical store refusing non Dutch cards.
Here are the following banks mostly used by international students in the Netherlands:
BUNQ
Bunq is an online bank (no physical branches) which is very easy to use for people who just arrived in the Netherlands because you do not need a BSN and all the content is available in English.
ING
ING provides content whose most of it is available in English and the company also has physical stores. Moreover, last but not least, its service is free of charge for students!
ABN Amro
From my experience, ABN Amro is the card the most used by students. Indeed, most of my friends have a subscription within this bank because all informations are provided in English, a physical branch is located in the city center of Groningen which can always be useful in case of an emergency or an issue that you know would be way fastier to solve with an advisor sitting in front of you than online.
Phone package
Concerning the phone package, it is actually easier to keep your French package if you have an international phone package and therefore, gigas to use abroad. The only people I know who have decided to take the plunge by opting for a Dutch number are international students doing their entire Bachelor's degree in Groningen. So it's definitely worthwhile for them to start the process with a Dutch company, but the great majority of exchange students keep their home phone plan.
Dutch insurance (only mandatory to work)
As a resident of an EU country, you can easily use your European insurance card. If you intend to work, however, you will have to take out Dutch insurance, as companies are not allowed to employ anyone who is not covered by a Dutch insurance company. The most basic insurance costs a little more than one hundred euros per month. I chose to sign up for the Zilveren Kruis insurance with the addition of medical expenses so that it also covers the dental care fees. I knew that if I had a problem with my teeth, the costs could quickly become very high, so I wanted to make sure that the insurance would cover this. Each month I am charged €124.75, but I am reimbursed €111 by the government, as most insurance costs are covered below a certain salary.
A DigiD is needed to apply for a healthcare allowance. After you manage to get it, you can easily sign up by filling this form (unfortunately available only in Dutch): Inloggen op Mijn toeslagen (belastingdienst.nl).
Closing up, these administrative processes may seem hard to undertake, but I assure you that it is actually very easy to do. If I had managed to handle it, you can definitely do it as well! In my opinion, the Netherlands is a real administration-friendly country and this feeling is especially obvious coming from France, known as hell for those for whom administrative formalities are a tremendous burden. This way, there is no need to worry, everything is simplified for students and the vast majority of information is available in English.