How to fix this bug

I am making an mmorpg game, and I am having trouble fixing this error when I try to put my scripts on something. This is the error it says this the script needs to derive from monobehavior this is a huge issue for me. Is there any solution, if there is please reply thanks.

Every script on object must derive from monobehavior. Simple as that. Next time post your code and we’ll check. Until then:

Unityscript

class MyClass extends MonoBehaviour 

C#

class MyClass : MonoBehaviour

Not that i want to shatter your dreams, but you might wanna tune down your ambitions and start with something easier than mmorpg.