The setting Allow Guests to Checkout can be found by going to Settings >> Checkout Settings >> Global Settings tab. Changing this setting to Yes will allow customers to checkout without creating a customer account. Changing this setting to No will require customers to create an account to checkout. More information on Guest Customers can be found in the Customer Summary QuickGuide.
Similar to the setting Allow Guests to Checkout is the setting Allow Registered Users. This setting can be found on the Global Settings tab under Checkout >> Checkout Settings. When Allow Registered Users is set to Yes, customers are able to proceed through checkout using an account they have set up with the site. This allows the customer's information that they have on record to be automatically filled in when they enter checkout. Registered Users can also log in to their account to view orders, update their profile, and change their password. More information about the My Account Pages can be found in the My Account Pages Quickguide.
The setting Two Step or Four Step Checkout can be found on the Global Settings tab under Settings >> Checkout Settings. This setting controls the number of steps a customer must go through in order to complete the checkout process. More information about the 2-Step and 4-Step Checkout processes can be found in the Checkout Workflows QuickGuide.
To change from your MonsterCommerce Shared SSL to your own SSL, you can purchase yourn own SSL Certificate through www.netsolssl.com. More information on purchasing your own SSL can be found on the second page of the Site Security QuickGuide. For more information on SSL in general be sure to read the first page of the Site Security QuickGuide.
Buttons for navigating through the checkout process of an e-commerce site should be large and easy to find. MonsterCommerce offers several free button sets that have been optimized to help increase checkout conversion. They can be downloaded from the MonsterCommerce Small Business Website.