Making a Strategy turn based game similar to TFT (TeamFight Tactics)

I'm in my third year in computer science and this semester I have a Java project to make. so my instructor told us we have to make a strategy turn based game called TFT, even the characters are the same. I have very little experience in building games.So this is my first "BIG" project really.

The instructor gave us a general Class Diagram of the game but there are still a lot of unanswered questions about design patterns in the Diagram of the game. the Class Diagram is contained here in page 5 https://drive.google.com/file/d/1OV8fRTAaMEC-O_NafZZf1GD4ANOoDynW/view?fbclid=IwAR1_N9alZQXlcUcmt_tg-fKrKJCI4qvm1Ec9dsEHMIM21j5DZwB9dfxlaa8

i have the following questions:

What is the use of the DamageFactory?

what is the use of the RoundManager?

some abilites stay activated for a couple of rounds, how do i ensure this happens?

Why is there no need to make a class for every Champion and let them inherit from a champion class which has common features and attributes?