textFormat Object question - probably an easy answer

I’m trying to modify a matching game for a project I’m doing. I am extremely novice at AS so excuse the “dumb” questions I may come out with.
Right now, one problem I’m having (the smallest issue, but the easiest to solve) is with trying to set text properties of text fields.
Here is the Actionscript below:

           // font format
            var gametxt:TextFormat = new TextFormat();
            gametxt.font = "Arial";
            gametxt.size = 24;
            gametxt.bold = true;
            // the score  
            gameScoreField = new TextField();
            gameScoreField.x = 60;
            gameScoreField.y = 40;
            gameScore = 0;

I do not get any compiler errors, but the text remains unaffected.
So, what am I doing wrong? There must be something missing…