Accessing other scripts in C# with Visual Studio.

I have only used unityScript up until now, but now I have to change to C# so I’m not that good at it. This might be super basic. Here is a example taken from unity’s website.54193-02a2d16b7ae08c3ee8d513fe29800b24.png It’s an example on how to access other gameobjects via script, and it’s in C#. As you see they set the variable type of the other script with the name of the script, “OtherScript”. When I try to do this Visual Studio says that it does not recognize the usage. Is this a old method of writing type of scripts?

All the scripts have to be C# for Visual Studio to work correctly.