New to Java

Hello

what is the use of this keyword in inheritance? is it to access methods in child class I write it like this:

Parent p = new Child();
if (p instanceof Child){
  
    Child c = (Child) p;
  
}

now when I write p.getName(); which the method is defined in the child class only not in the parent class. it would return the value name of the child class?
I couldn't understand this tutorial I read it in the tutorial page about the Bike.

thanks