Unity won't open!! Do I need to install something for Unity??

Whenever I try to open a C# file, it only opens the text reader, which doesn't allow me to edit the script.
Is C# something I need to install separately from Unity? Does it not come with it?

I feel like an idiot because it's probably something really simple like I need to install C# online or something, but any help would be greatly appreciated.

 

As you can see, only the text reader has appeared, meaning I can't edit the page at all.

 

No idea what "Text Reader" is. Looks like adware. I mean, it has adverts lol

Are you opening these files from inside unity, or are you opening them from windows explorer?
Try to open them from inside unity. If you installed the default setup, then it should open up in a program called Visual Studio (Community)

If it doesn't open up in that, you might have excluded it when installing perhaps. There are other editors you could use, which is why someone might exclude it.

See if you have it installed.
If you don't have it installed, then install it. Visual Studio 2019 Community Edition is fine.

In unity via the top menu, set the editor as the editor to be used:
Edit -> Preferences -> External Tools
External Script Editor = Visual Studio 2019 (Community)