Overloading >> and << operators

I'm attempting to teach myself C++ and up till now its been fairly easy. I'm having tons of issues understanding overloading operators and specifically overloading >> and <<. I've been going to many sites trying to figure this out and even am using some sample code to try to give myself greater understanding. This is what I have so far in code.
In class Rectangle:

Code:

friend istream& operator>>(istream& inputStream, Rectangle& Rect);

I believe this should be done in main, but can’t see where they are doing it.

Code:

istream& operator>>(istream& inputStream, TRectangle& R)
{
    cout << "Length: ";
    inputStream >> R.Length;
    cout << "Height: ";
    inputStream >> R.Height;
 
    return inputStream;
}

I keep getting a compile error on line

Code:

istream& operator>>(istream& inputStream, TRectangle& R)

saying that I need a ';' before { but none of the syntax i've found anywhere has this ;. If I remove this bit of code, I no longer get the compile error so it has to be here.

Any help with understanding overloading >> and << would be greatly appreciated.

In main? The operator should be overloaded outside of main. Usually, I put it above main or in a different source file with the rest of the class implementation. It's like a function. Their defined outside of main.

Hopefully no errors -

Code:

#include <iostream>

class thing
{
private:
	int x;
	int y;

public:
	thing() : x( 0 ), y( 0 ) {};

	friend std::istream &operator>> ( std::istream &in, thing &instance )
	{
		std::cout<< "Enter X value: ";
		in >> instance.x;
		
		std::cout<< "Enter Y value: ";
		in >> instance.y;
		
		return in;
	}

	friend std::ostream &operator<< ( std::ostream &out, thing &instance )
	{
		out<< "X: " << instance.x << "; Y: " << instance.y;
		
		return out;
	}
};

int main( void )
{
	thing instance;

	std::cout<< instance << '\n';
	std::cin >> instance;
	std::cout<< instance << '\n';

	return 0;
}

That's just some code I made ages ago so I wouldn't forget how to do it. I think it works ...

Well I feel like the idiot of the day. I've been working on this for over 6 hrs now, and had no other choice but to post here. Moved it out of main, and it works like a charm. Thanks for the help guys. Now just have to figure out how to output in SVG format, lol. Fun!