Stumbled on the following details that look to be still undocumented by Oracle. Here is how you can create a theme for the Classic UI within Oracle Sales Cloud by completing the following process:
- Click Navigator -> Setup and Maintenance
- Search and Go to Task “Manage Menu Customizations”
- Expand Customization
- Highlight Themes and Show Component
- Click Close
- Now go to the Navigator Menu and Customization and then Themes
Now you are ready to start the process – enjoy!