Once you have brought up a script's window for editing, you can add controls to that window.

You'll see a small window labeled "Toolbox". When displayed, the Toolbox always stays above other Programmer Center windows. This window contains 3 rows of buttons representing the various types of controls you can add to the window. Below these "control buttons" are two more rows of buttons for various editing operations you can perform on the window and its controls. Right now, most of these "operation buttons" are grayed out (ie, you can't select them). This is because you haven't yet placed any controls in your window.

As you move the mouse pointer over any button in the Toolbox, and leave the mouse hovering there, a small yellow label will pop open to tell you what the button is for. For example, shown below is the mouse hovering over the "control button" that looks like a slider. Sure enough, the label reads "Slider" as so:

Click (the left mouse button) on this slider button to choose it. Now move the mouse pointer over the blank area of your window. You'll notice that the mouse pointer changes appearance as you do so. The mouse looks like it is grabbing a moving box as so:

Click the left mouse button somewhere in the blank area of your window. You'll notice that the mouse pointer changes back to its normal appearance, and a slider control has appeared in the window. You have just added a slider control to your window.

You can now choose another type of control in the Toolbox, and drop it somewhere inside your window, just as you did with the slider.