Alright, maybe I am not doing it properly, but I need some advice on this.

Basically, I am looking to fill the rest of my timetable with optional courses and units, and so far I have few ideas on what I could choose (note a third-year, Sociology Honour student). Unfortunately, there seems to be some trouble I am having. The enrollment date has been fixed, thankfully, so I am trying to prepare myself by taking on some courses already. My grades are great so I am looking to see where could I go for next.

Strangely enough, whenever I click to search for second or third year courses, it could not find it, despite the fact some, keyword here some, first year classes were still found. I tried for example take a year two anthropology class (the prerequisites were at least three units of Level I anthropology and registered in any program, I have taken two Level I Anthropology courses before) but it could not find it. I checked the Undergraduate Calendar for this year, and the course is still present. Another I tried to take was Level I of Social Psychology course, but it would not find it. What am i doing wrong here? Any advice or insight would be helpful.

Have you tried looking up the actual course in the master list on mosaic and try adding it there?

Dude, at least you have classes to add, I don't even have Capstone listed in my requirements for whatever reason, and this is my last year.... what the fuck.....

Where is exactly that master list of classes?

Go onto mosaic->student centre->plan->course catalog