Anmeldung, the paperwork clock starts now
If you have moved to Switzerland in the last two weeks, this is the single most important thing you will do this month.
Every canton requires you to register (Anmeldung) at the Kreisbüro or Contrôle des habitants or Ufficio controllo abitanti within 14 days of arrival.
Bring your passport, your rental contract, your work permit or job contract, and your marriage or family papers if relevant. The list varies slightly by canton, but never by much.
Miss the deadline and you can be fined. Register on time and everything else, bank account, health insurance, tax, becomes easier because you now have a Swiss address.