You don't really draw a pattern, per se. Instead, you draw shapes that are filled with a pattern.
- Open the Shape Style window if it isn't open already (Window > Shape Style).
- Click the Pattern button.
- Click the color well just to the right of the Pattern button. This will open the Pattern Fill dialog box.
- Click the drop-down menu in the Pattern Fill dialog box and select a pattern.
- Select any LayOut shape drawing tool, such as the Rectangle tool or the Circle tool.
- Click once in the drawing space to anchor your shape, then move your mouse to expand the shape. You should see the pattern fill your shape. If not, make sure that the Fill and Pattern buttons are both depressed in the Shape Style dialog box.
- Click a second time to finish drawing the shape.