Context can refer to several different things. First, how will your audience use your technical document? Does it need to be printed, or an e-document? Should it even be a document or would a video or audio recording be better?
Another way to think of context is to consider what will influence your audience as they read your document. Are there political, cultural, or even environmental considerations that you need to think about. For example, if you look at a Japanese map of a city a swastika marks the location of a Buddhist temple. But it would be considered offensive to use a swastika in a document meant for a Jewish audience.
Think about your audience and the context that they will use your document. How does this influence your decision of what type of document to create? What else do you need to consider for context?
After you have planned out your purpose, audience, and context, then you need to plan your project calendar.