Gradient Background change

You can't directly change the color of the artboard. (There is a technique to do that, but it won't print or show in your artwork.)

I think that the step that is missing is that you need to draw a shape that covers the whole background before you'll be able to fill with a gradient.

dallena,

To elaborate on what Jane said, if you wish to make a customized (direction) gradient (in the same way) as in the class, you can ClickDrag with the Gradient Tool from a desired spot on one side to a desired spot on the other, or between specific Anchor Points, in any case spanning the whole background shape/outer path.

For other variations you may consider, you can ClickDrag entirely within the background to have the gradient shortened between areas with the solid end colours, or ClickDrag between ends outside the background to have a partial background.

For a specific angle of the gradient, just insert the angle in the Gradient palette.

And you can start with a default gradient and then change each end stop colour, and add one or more in between.

Or maybe you need to Show Options for the Gradient palette.

And then there is this help page,

Create gradients in Illustrator

and this tutorial,

Learn to use gradients |

If you are talking about a letter sized page, create a rectangle 8.5x11" > go to your Swatches palette and launch the Gradient swatches > select one of the default gradients ( you should see it fill your rectangle ) > with the rectangle selected, use the Gradient tool by selecting it in the tool palette > click and drag using the gradient tool and you should see the gradient transform to your click and drag.  Or open up your school file and review your notes.