When I was learning German, the teacher told me a rule for the Perfekt tense:
You conjugate the verb "haben" first and then add the Partizip Perfekt at the end.
An example such as
Sie hat an der Universität Moderne Sprachen studiert
satisfied my teacher's idea.
However, when I was reading a sentence today, this order did not take place.
Der Freund, der die Pasta gekocht hat, heißt Moses.
I was wondering, is the relativpronomen "der" causing this order to change? And, why is this the case?