hey guys can someone explain to me methods and constraints

Do you mean methods and constants? Rather than constraints?

I don't know any Java, but both Methods and Constants both appear in Ruby which I do know about (If I am wrong please someone correct me)

Constants are variables that you know are never going to change. I would create a variable to hold someone's age, which will ultimately change at some time and the variable can then be reassigned with the person's new age.

A Constant is a variable that will never change. I would use a constant when I want to store a piece of information that can be called upon in a program but never altered. For example, in a program that returns information about myself, I would store my name in a constant, because my name is never going to change. But I would store my age in a normal variable, because I could then change it later as I get older.

Constants are useful (and should be used) because they will trigger an error in your code if you attempt to change them later in the program. This is a great safeguard against accidentally changing the value of a variable that you would not want to ever change in your program.

I hope this makes Constants clearer for you.