I don't know how to use Generics on matrix operations

Question

Hello guys I have an issue, i've made the "regular" operations and operator overload with martices in C#, but my teacher told me that I should do those with generic types using IEnumerable and stuff, but without using functions from C# library to automatically sort things out, I guess I should create same functions using generics but I don't really understand what to do can someone help me ho to do these operations using generic types? I would really apreciate the help!

There's my code down below! If there are some issues Im open for corrections. And tips to improve. Im still coding this...

My question is: Ok imagine that I have a function that does the Union operation between two arrays A and B, how I should implement this operation by using generic arrays And then by overloading the '+' operator do the sum between two arrays. I hope this makes it clear.