Complex sentence: Mikligarður (an older Icelandic name for Istanbul) is the school's grand hall, used for graduation, dimmisjón, Morfís competitions, and choir practices.
Split into simpler sentences: Mikligarður (an older Icelandic name for Istanbul) is the school's grand hall and as such is used on multiple occasions. It is, among other things, used for graduation, dimmisjón, Morfís competitions and choir practices.