Once you receive and accept a job offer, the HR services of the institutions in Brussels and Luxembourg will help you find your way and settle in. In particular, they can help you find accommodation (including vetting your rental contract). Information Days are also regularly organised to help partners of new staff to settle into life in the new country.
Both Brussels and Luxembourg offer excellent national, European and international schools. The above-mentioned services can put you in touch with crèches, playgroups and other facilities.