The home screen is https://www.digicert.com/account/login.php
After logging in you will see the main menu (which recently was restructured)
Account : My Division and Users (and Guest URLs and API keys)
Your Divisions and users can be managed here, including Guest URLs, API keys and Two-Factor authentication
Orders : Orders, Requests, and Request a Certificate
Here is where you request and approve certificates. You also see previous orders.
Validation : Organisations and Domains
Here you can create new Organisations and divisions, but you also find all the ones already created together with their status.
A number of tools that can help you in common tasks. Note that the CSR Generators tool brings you to a page that contains a long list of products for which support data is available. You don't know how to handle certificates for an F5 or a Barracuda? It's all near 'We also provide detailed instructions for other server types.'