I do not know of any tutorials with regard to NVDA and web-based Office. Given the fluidity, or potential fluidity, of the web based version I would be disinclined to use it if I had any other choice. With the advent of the recycled license marketplace, most active on eBay but also plenty active elsewhere, it is a simple matter to get a legitimate recycled license for Office 2016 Pro Plus (or pretty much any edition, but that's "top of the line") for under $10. I've now installed on 6 machines using recycled licenses, and had trouble twice, once being issued a second key and once a refund.
Three examples currently available (and there always seem to be plenty offered in the under $10 range):
Microsoft Office Pro Plus 2016-Full Version 32/64bit-All Languages key
genuine Office Pro Plus 2016-Full Version 32/64bit-All Languages-Activation key
Office Pro Plus 2016-Full Retail Version 32/64bit - Activation key.
If you plan on using any of the programs that are part of the Office suite heavily during your academic career I'd either purchase a recycled license or see if your school has an agreement for licensing for students and faculty through Microsoft at a reduced cost.
Brian - Windows 10 Pro, 64-Bit, Version 1809, Build 17763
Growth for the sake of growth is the ideology of the cancer cell.
~ Edward Abbey