Students typically do 4 x 6 credit point units of study per week. In first year, a typical unit is 5-6 contact hours per week (hence 20-24 hrs). and in later years it is 4-5 hrs a week.
But you have outside study as well - be prepared for the equivalent of a full time job (35-40 hrs week) effort.
Most have to go 5 days - only by luck of timetabling or subject do engineering students get a day off.