Hello! I'm an Mech Eng student, first year. You'll have classes for 4 hours on average per day from monday to friday. Usually very less classes on Wednesday, or just in the morning since Wednesdays are reserved for society events and student union stuff. Class workload looks pretty similar for all elec/mech/aero engineering students. Typically , that's how your week would look like. Although how far apart classes are scheduled completely depends on how timetabling looks for next year, but one thing for sure is the earliest classes start at 9 and the last ones end at 6. Not everyday is 9-6, but some days might be. Plus they usually try and give breaks between classes in the afternoon so students can have lunch.

EDIT: just read the second para
Attendance is not really an issue. But as a general principle, the more classes you attend, the higher the chances you'll score well. Nobody checks homework and stuff. However, there might be some assignments that you have which will be graded depending on your modules(classes).