The checkout page template should contain cart, summary information, shipping and payment system widgets. Just like for any other page template, your checkout page template can include any number of widgets, tokens, or even front-end editable content areas. Feel free to create any number of checkout templates as required to perform checkout page conversion tests for your web store.
And since you are preparing your checkout page template, it is a good time to clarify a couple of points at this stage. As you can see in screenshot #2 below, the checkout process offers existing customers the ability to log-in prior to completing their purchase. There is no way to "create" an account because the system does it automatically for your website visitors. Simply comment the DIV containing the "existing customer log-in" column out in your code if you wish to bypass this option altogether, and make sure to remove any action email trigger so that no email with credentials gets sent for first-time buyers.
Now is also a good time to think about your shipping policy (do you offer free shipping, how will you handle shipping charges? will you mark up shipping? do you let people pick their orders up at your storefront?) then go to the STORE/shipping config menu to download, install the appropriate real-time shipping gateway plugins. Pick also your payment gateway and consider offering free quotes as a checkout option (Website Builder features a very comprehensive built-in web quoting software engine that is ideal for merchants also making sales over the phone). All shipping and payment plugin tokens are added to the default checkout template, and show up automatically when the plugin is found to be installed and operational on the system.
Here is an example of what Default checkout process looks like: