I’m an international student at Aalto University. One of my dream jobs after graduation is to become a librarian. What are the requirements for such a position? How and where can I find available spots in the job market?
You could start by contacting the Aalto University Library. https://learningcentre.aalto.fi/en/
Perhaps you could get there for an internship.
The library can be studied in, for example, Keuda, where there are professional courses for immigrants.
The language requirement for studying is Finnish B1.1. https://www.keuda.fi/koulutustarjonta/koulutushaku/tutkinnot/maahanmuuttajille-suunnattu-kirjastoalan-koulutus-tieto-ja-kirjastopalvelujen-ammattitutkinto-at
Not everyone working in the library is a professional in the field. You didn't tell what you're studying. Maybe you already have the skills that interest Libraries.
You may want to follow job search notifications on, for example, Kirjastot.fi. https://www.libraries.fi/