asterisks with geometric shapes using OOP [closed]

first of all, English is not my native language.
I’m learning OOP with PHP and it’s hard for me to do this exercise, I know it’s not the best way to learn but I need something to start with.
Attached exercise.

translation of the exercise:
Part 4 – Exercises with OOP Application No 19 (Geometric Figures) The GeometricFigure class has: all its protected attributes, a default constructor, a getter and setter method for the _color attribute, a virtual method (ToString) and two abstract methods: Draw (public) and CalculateData (protected). CalculateData will be called in the constructor of the corresponding derived class, its functionality will be to initialize the _surface and _perimeter attributes. Draw will return a string (with the corresponding color) forming the geometric figure of the object that invokes it (return a series of asterisks that model the object). Example:

  *   *******
 ***  *******
***** *******

Use the ToString method to obtain all the complete information of the object, and then draw it on the screen. Class Hierarchy:

Class diagram