Hello Farhan:

I am not sure why you think you should be able to get Microsoft Office training materials with NVDA for free. Significant work is required to create and maintain training materials, especially when you consider the ever-changing feature set of NVDA and Office and that many people are using different versions of each. If sighted people want training materials to assist them in using office products (via books, webinard, classes, etc.) they pay for those services. I would expect that the blind community would do the same. As Quentin pointed out, there are several tutorials available from NVDA on Office product, specifically tailored to NVDA, that can be purchased for a nominal amount. These tutorials start with the basics but also cover advanced topics.

If you want free, search the web. Searching the web, Microsoft also has some web pages devoted to providing assistance to using Office products with a screen reader. While these are not NVDA specific, many of the examples use Office built-in keyboard shortcuts not specific to a particular screen reader, so that they can be used with NVDA.

https://support.office.com/en-us/article/Use-a-screen-reader-and-keyboard-shortcuts-with-Office-apps-4aba5a56-f80c-4a6b-a584-d0f415471617

One of the best ways to learn to use the Office products is to play and experiment. The key is to know how to use the ribbon. Gene and others have posted numerous tutorials on how to use the ribbon. Using the ribbon effectively is key, since it also appears in other Microsoft products, like Windows Explorer. NVDA speaks keyboard shortcuts as you navigate the ribbon, so for commands you perform regularly, you can learn these shortcuts and become more proficient. Also, learning Office shortcuts rather than scree reader specific shortcuts means you can use multiple screen readers effectively.

Rick