I had to sign up for all of my own classes in Madrid with very little advisement or help. This website was incredibly helpful. It explains a little bit about how the Spanish Higher Ed. system works and explains some of the technical vocabulary.
One of the things that surprised me the most about the system at the Universidad de Complutense was that everything was done on paper. When I enrolled for a class, I had to give a 'ficha' or card of personal information with a photo to my professor. Then I had to fill out a form showing which classes I was enrolling in and take it to the ERASMUS (European study abroad) office. This made everything go slowly. I spent the first three weeks of each semester trying out classes before actually enrolling in them.
While I was at the Complutense, they were in the middle of trying out a new system based on the United Statesian way of doing things. The trial classes included things like mandatory attendance, homework and midterms. God forbid! Globalization changes everything.