There are two variations, the Rectangle tool and the Grid tool:
The Rectangle Tool draws a shape with four sides and four right angles. Click at one corner, and then draw to the opposite corner. To draw a perfect square, hold either the Shift or Ctrl key on your keyboard before you draw. Click at the center of the square, and then draw “outward” in any direction.
The Grid Tool draws a grid—a series of overlapping horizontal and vertical lines. The default size of the grid squares will vary with the current line width setting. The thicker the lines, the bigger the grid squares.
Once a grid has been drawn, you will see that it has three handles, or white squares, that you can click and drag with the mouse. The handle at the top-left of the grid allows you to move the entire grid. The handle at the bottom-right of the grid allows you to resize it. The handle in the interior of the grid, near the bottom of the first square, allows you to adjust the grid spacing. V1 Pro will remember your grid spacing for subsequent grids.