Objective C - How do I use initWithCoder method?

I have the following method for my class which intends to load a nib file and instantiate the object:

- (id)initWithCoder:(NSCoder*)aDecoder 
{
    if(self = [super initWithCoder:aDecoder]) {
        // Do something
    }
    return self;
}

How does one instantiate an object of this class? What is this NSCoder? How can I create it?

    MyClass *class = [[MyClass alloc] initWithCoder:aCoder];