Open the downloaded file in Photoshop. In the Layers panel, select the "Step 1" layer. If you don't see the Layers panel, go to Window > Layers.

Select View > New Guides From Shape, which creates guides in your document based on the dimensions of the object in the selected layer.

Select View > New Guide Layout, which opens the New Guide Layout dialog box. Select the Clear Existing Guides option to remove the guides you made in Step 1. Select the Preview option so that you can view changes to your guides as you specify new guide settings.

With the New Guide Layout dialog box open, change the Preset from "Default" to "12 Column." Notice that Photoshop creates the gutters (or the spacing) between columns automatically based on the number of columns you have selected.

Within the New Layout Guide dialog box, select the Rows option and change Number to "6." For the Gutter value, enter the same value that is used for Columns, "0.278 in" (or 20px). See the changes reflected as you preview your document.

In the New Guide Layout dialog box, select the Margin option. Enter "0.278 in" (or 20px) for the Top, Left, Bottom, and Right margins (the same value you specified for Column and Row Gutters). The columns and rows shrink to accommodate the margins.

Click OK to finish creating your grid of guides.

To bring an image into your document, go to File > Place Embedded and select “step-6.jpg” from the practice files you downloaded. Click Place.

Drag the image to arrange it as shown in the illustration (right). Press Return or Enter to commit to the placement.

In the Layers panel, click the small box next to the “Step 7” folder, which causes all layers for Step 7 to display in your document. Click the arrow to the left of the folder icon to expand and show all of the layers and objects for this folder.  Move the objects on each layer around to create a unique composition, using the grid to align and arrange the elements.

Tip: You can quickly reveal or hide guides by pressing Command and ";" on Mac, or Control and ";" on PC keyboards , or select View > Show > Guides.