You have to search the web. There are a number of free resources online. The trick is finding them. Here are links to some resources I've found online. A key point to remember is that there are not any really significant changes to BASIC functionality
going back as far a 2003 (and even a bit earlier). So if you find a course or manual for an earlier version, the concepts very likely still apply. The only thing that may have changed is where the commands are hidden. 2010 and 2013 can use the MS Labs "Search"
tool to find most commands, and 2016 has the built in "tell me" feature (an unfortunately dumbed down version of the search command tool).
http://www.free-training-tutorial.com/microsoft-word-online.html - free online tutorials, looks fairly extensive
http://www.microsofttraining.net/microsoft-training-manuals.php - download free training manuals
https://support.office.com/en-us/article/Office-365-scenario-based-training-af07cb6b-980d-4f33-8599-322582767408?ui=en-US&rs=en-US&ad=US
- Office 365/2013 Business focused tutorials
http://www.gcflearnfree.org/office2010 - Free Office 2010 Training
http://www.brighthub.com/computing/windows-platform/topics/microsoft-word.aspx
https://technet.microsoft.com/en-us/library/jj871004%28v=office.16%29.aspx?f=255&MSPPError=-2147217396 - MS
"quick start guides" and "What's new" - short overviews
https://education.microsoft.com/Start/LanguageSelect?ReturnUrl=%2fgettrained%3f -
MS educator site has lots of learning materials
https://support.office.com/en-us/article/Office-Training-Center-b8f02f81-ec85-4493-a39b-4c48e6bc4bfb?ms.officeurl=training&ui=en-US&rs=en-US&ad=US -
MS Training Center, basic learning tutorials
https://www.microsoft.com/en-us/download/details.aspx?id=22781 - **MS Learning Essentials,**is old resource, but you may find some useful stuff in it.
https://www.microsoft.com/en-us/learning/default.aspx - MS Learning site
https://mva.microsoft.com/product-training/office-365#!index=3&lang=1033 -
MS Virtual Training Center - courses for IT Pros, you may find one or two useful
https://mva.microsoft.com/training-topics/imagine-educator-resources#!lang=1033 -
MS Virtual Training Center - Educator Resources
https://blogs.office.com/2013/03/19/free-office-webinars-every-tuesday-watch-videos-anytime/?inf\_contact\_key=afeb69c9209c5a55c4cb63625353f5b5e7620ec00602e748ad2a1750e0f637ae -
15 minute webinars on various subjects
https://www.youtube.com/playlist?list=PLXPr7gfUMmKyE22-YpbgcDfr2SXEO7-qX - Sway tutorials (new online approximation of PPT, pretty neat)
Also take a look at this other question, I have been posting various training links. You may find a few more useful links there