Can't add script (Unity Playground)

Hello,

I follow the "How to Start Making Games - Unity Playground" Tutorial Video and at 3:30 a script is added to a object via the "Add Component" button.
However, when I try to add that script, it doesn't show up.
I tried drag and drop it on the spaceship and it told me that it needs to derive from MonoBehaviour.
I googled that and found out that I need to add said MonoBehaviour to the code, which I did.
But it still says that it needs to derive. (see pic)



Do I need to add something else to make it work?
Why is that "MonoBehaviour" neccessary and are there other types?

Thank you for your time.

 

I got it to work. I reinstalled Unity alltogether since I had other/and similar problems with all the tutorials. That made me suspicious that maybe it had something to do with my pc.
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