The work week is Wednesday to Sunday, with Monday and Tuesday off. I am unsure of the actual times for teaching, but it is stated that it is "6 hours of office hours per workday (12am-18:oopm)".

Check the times. If I had to make an educated guess based on the content of the contract and personal experience I would expect that most weekday class will begin after 6pm ie after the office hours, and you may continue teaching until 9pm. Weekends could see you teaching from the morning to the evening possibly with a split shift.