When you select the "New Resource in …", you'll see a new dialogue window appear titled Create Resource. Make sure you have Gradient selected and then click on the Create button.

Once the Create button is clicked, the Create Resource window will change into the Gradient Editor window. Here you are able to change the spot color of the gradient and add more spot colors.

To change the spot color, click on the square next to color to get the color picker to appear. Select the color you want and then click on OK. Do this to all the Spot Colors if you want to change the color. If you want to add more Spot Colors, move the mouse close to one of the existing ones and then click. This will create a new Spot Color that you are able to change. To delete a Spot Color, click (while holding down on the mouse) drag the Spot Color away from the Gradient Line. To fill an object with a Gradient fill, click on the Fill Color in the Attributes Palette and select Gradient.

If you have multiple Gradients and want an object to have a particular gradient, click on the Fill Gradient Settings button in the Attributes Palette and change the gradient to the one you want. Click OK to close the window and have the object take the new gradient fill.