1991 Volkswagen Golf No heat

I just bought a 1991 vw golf for very cheap to hopefully last me a few months in the winter. The heat does not work, and since I live in Maine, it is a big deal. I have been doing lots of research on the internet and have discussed it with my dad and we are not sure what it is. I have the gist of how the whole system works, but is it a difficult job? And what steps would be best to take first and how should I go about doing them?