Family is for parents and siblings. Relatives is for aunts uncles cousins nieces and nephews

Relatives are group of people related by blood or marriages, family consists of people related living together, so a family can be a group of relatives living together

You can still consider (relatives as a family) but if you want to distinguish between the two you could say In my *immediate family* we have 4 members which include for example you, your parents, and a sibling. Whereas the term *family* can be used for both your (immediate family) and (relatives) it depends on which context you're using it. But most commonly we use family to refer to our parents and siblings while relatives are relations based on blood or marriage which can include your cousins, In-laws, uncles, and aunties.

In American English "family" is a fairly loose term, typically meaning your immediate relatives or possibly even people you feel a particularly close connection to and live together or have lived together with in the same household: father, mother, wife, husband, brother, sister, children. "Relatives" are typically people you are connected to by blood or marriage, but don't have the same close relationship with.