Never ever wrote a script and have trouble with an error.

Ok big noob here, I’m pretty young but I chose creating games as a career for my life. The problem is that I have very little knowledge in Unity or scripting so I went to the tutorials and I’m currently following the “Roll a Ball”. I copied the first script they wrote in the tutorial but when I went to play the game to test if it works I got this error, and it says “NullReferenceException: Object reference not set to an instance of an object
PlayerControllerBall.FixedUpdate () (at Asse!ts/Scripts/PlayerControllerBall.cs:21)”. Once again I am a big noob so the simplest answer would be much appreciated. But as a new comer any starting off advice in game devloping would also be nice, thanks for the help53239-screenshot-1.png

Your void start function should be void Start… Note the upper case S. Most programming languages are case sensitive so start and Start are not equivalent.

Because of this, Unity isn’t calling your start method, so rb never gets assigned to the Rigidbody.