Making a simple C# script to change 3D text

Hello,

I want to create a C# script that changes the text of a 3D text object on Start().

I dont understand how you get handles to existing objects. For example, suppose I would attach the script to the 3D text object, here's how I can imagine it would look like;

 void Start() {
    this.text = "asdf";
 }

It dosnt work or compile obivously. How do you actually grab the object and then manipulate its attributes, like its text?