VERSION FRANÇAISE (en cours de traduction)
WP eStore doesn't require you to have a specific checkout page. You can place the standard shopping cart anywhere on your site and it is capable of letting your customers checkout from where it is being displayed.
However, if you want to create a separate checkout page then you can do that too. A separate checkout page can be useful for the following:
i) Add checkout/payment related messages to give more guidance to your customers
ii) Show/offer some upsell products on your checkout page
Create a Specific Checkout Page
Step 1) Create a WordPress page called "Checkout" (You can give it any title you want)
Step 2) Place the following shortcode on this page:
Step 3) Add any other messages or upsell products on this page and save the page.
Step 4) Go to eStore settings menu and specify the URL of this checkout that you just created in the "Checkout Page" field.
The following two steps are optional but can be useful for some sites
Step 5) This step is optional. Check the "Automatic redirection to checkout page" field from eStore settings. This option will redirect the visitors to the Checkout page after they add a product to the shopping cart.
Step 6) This step is optional. Add a compact shopping cart widget to the sidebar of your site. You can use this to show a compact version of the shopping cart on your sidebar. This gives your visitors a visual indication of how many items they have added in their shopping basket.