Interesting fact: 'au pair' means on 'equal terms'. Au pairs work with a 'host' family in child care and support. You might help with a young child or baby or several children in a family. Equal terms means that you might opt to have language lessons in exchange for duties such as babysitting or helping with light housework, as well as general day-to-day care for a child.
Au pairs and families work together to find out what is a reasonable set of terms for the placement. Au pairs often have their travel paid. You may have to shift your expectations of a weekend and have two days off in the week to cover for the family at the weekend and so on.
Au pairs often work to improve their language or to get to know a country and a family and they don't always have to have specialist knowledge or necessarily formal childcare training. They are not entitled to the minimum wage as they are treated as a member of the family. Do your research on agencies, hours, contracts and agreements.
You will work out a contract between yourself and your employer or 'host' family. You will be responsible on a day-to-day basis for helping for a set amount of hours in care of the child or children. You are a reliable, dedicated caregiver with a love of children and you might have ambitions to further your career in childcare. In a live-in position, you might work extra hours doing baby-sitting and 'fit in' with the family. You need to be a confident, outgoing person, willing to join and collaborate in a family setting and be able to contribute informally to the education of the child in terms of play and behaviour. You will need to provide solid references and in some cases a CRB check or formal childcare qualifications.