Where am i going wrong with my code ? the challenge is not like prev ex in video

Follow the error messages. The first one you receive is:

Did you define your Square class as an inner class of the Polygon class? Be sure to define the Square class before or after the definition for the Polygon class

You did. Just need to adjust some brackets so that Square is defined after Polygon.

The next error you receive is:

Does your Square constructor take a single parameter named sideLength

Check the case of sideLength. S should be lowercase.

The last error message you receive is:

Did you initialize the field 'numSides' to 4 in the base constructor?

You need to initialize numSides to 4

What Exactly is wrong with my brackets? it wasnt extactly went over like this in the videos they had seperate files for the classes

Based on your brackets the Square class is inside the Polygon class. You have (some code omitted)

class Polygon
{
     class Square : Polygon
     { 
     } 
}

It should be:

class Polygon
{
}

class Square : Polygon 
{ 
}

namespace Treehouse.CodeChallenges { class Polygon { public readonly int NumSides;

    public Polygon(int numSides)
    {
        NumSides = numSides;
    }
}
class Square : Polygon
{
    public readonly int SideLength;

    public Square(int sideLength) : base(numSides = 4)
    {

    }
}

}

how is then done is the base constructor initialize numSides to 4 this was never went over in the video