You can have the only the Online Editor subscription or a Machine Translation Language Cloud + Online Editor subscription.
See the video on the Online Editor Getting Started page: http://www.sdl.com/languagecloud/online-editor/getting-started.html
1. This menu is from a subscription that has also the Machine Translation subscription.
You have to click on Documents to open the Online Editor
In the Documents window you can drag and drop a file or browse for it on your computer.
This will open the file in the Online Editor and will allow you edit the translation.