Market Admin said:

I'll elaborate a little on Icy's description and eventually add this to the “How to” section.

Here's the step by step instructions for setting up the grid layout store page function.

1.  Log into your backend WordPress administration area.

2. Click on the “Write” tab, and then click on the “Page” submenu option.

3. Type the word “Store” in the title box.

4. Scroll down the page and click on “Page Template“.

5. Select “Storefront Homepage” from the Page Template dropdown box.

6. Scroll back up to the top and click on the “Publish” button.

That's it.  This will add a page named “Store” to your menu options.

Additional Option:

If you'd like to make this grid view layout  your homepage when someone lands on your site, follow the steps above and then do the following:

1. Click on the “Settings” link within the backend WordPress administration area.

2. Click on “Reading” within the navigation submenu.

3. In the section labeled “Front page displays“, click the button next to “A static page“.

4. In the dropdown box labeled “Front page“, select ”Store”. (Or whatever you named your store in step 3 above in the previous section.)

5. Scroll down and click on the “Save Changes” button.

That's it.  That will make your “Store” page the first page shown when your website is accessed.  If you ever want to reverse this process, just go back to the “Reading” section of the “Settings” area and switch the radio button back to “Your latest posts” and save your changes.

I don't have "Store" as an option in templates. I'm using my own WordPress theme, could that be the problem?