Tutorial #1
ABSTRACT LINES PATTERN 1. Create a new document (File --> New or Ctrl/Cmd-f) with dimensions 600 by 600 points.
2. Select the Rectangle Tool (m) in the Tools Panel. While holding down shift, draw a rectangle from the top left corner of the artboard to the bottom right corner. With the rectangle still selected, change the fill and stroke to None (Shortcut way: / --> x --> /). Lock the rectangle in place (Ctrl/Cmd-2 or Object --> Lock --> Selection). Deselect the rectangle by clicking outside the artboard.
Rectangle Tool
Make sure both the stroke & fill are None.