Timetable Help!!

Ok I am completely confused about my timetable.. My course is dt228 year 1 week 4-13 etc.. can some1 plz explain what is with dt228/1,dt228/1a 'b,c,etc.. I dont know which im in last name c if it alphabetically or sumting.. anyways i get even more confused about the email I received about the timetable and i will quote it

''Please note that only lectures will take place next week, labs and tutorials will not take place next week, unless your lecturers tell you otherwise.

Your first class will be a lecture with Richard Lawlor, your Problem Solving lecturer, on Tuesday at 3:00pm. (There is an error on the Monday timetable, you will have labs at that time, not lectures.)''

On my timetable , Monday is all labs and 1 lecture at 2 but i think the lecture is a mistake as it says above.. so basically do i go in monday for labs? Furthermore do i attend neither labs nor tutorials and only lectures so confused