my script is opening as text document and not in Assembly-CSharp

I created a folder in assets called scripts and made a script in it. when I double click on the script, it opens it in something called textEdit as a plain text document (I should also say that I am using a mac. the version of Unity is 2019.4.8f1. I don’t know what version VS is.) if I right click on the script and use open C# script, it open in VS but not with Assembly-CSharp. If I write my script sans Assembly-CSharp and press play in Unity, Unity says that I have compiler errors. please help.

I believe you didn’t linked Visual Studio with Unity ? (Edit => preferences => externals tools => scritp editor)