The video uses Mendeley on a Mac. The Citation Plug-in within Word for Windows will be under the References ribbon and will be labeled Mendeley Cite-O-Matic. For more details in using the Word Plug-in please refer to Using the Citation Plug-in
Note: There is a slight difference with MS Word on Mac: The Cite-O-Matic will appear as its own toolbar on a Mac.
Once you have your documents in Mendeley, you can cite and reference them within Word and LibreOffice by installing plug-ins. Once installed, you will have tool bar buttons that will allow you to cite a document, generate a bibliography, or manually edit any entry.
Go to Tools > Install... and select the plugin you wish to add. (Word must be closed.)
When creating a paper, click on Insert Citation in the toolbar to cite a document from your Mendeley Library.
If you are using Word on Windows, a box will appear allowing you to search for references by author, title or year.
When you find the reference you want to cite, click OK and you're done. You can cite multiple references by using semicolons to separate them.
If you prefer to find references using Mendeley Desktop, press the "Go to Mendeley" button beneath the search box, which brings up Mendeley Desktop. Then select the document in Mendeley Desktop, and click Cite in the Mendeley Desktop Toolbar.
Again, you can cite multiple documents. Just hold the Ctrl key and left click the documents you want to cite.
You can select your preferred citation style in the drop down menu. Additional styles may be added to your list of installed styles. See the box below for instructions.
Generate the bibliography by clicking Insert Bibliography.
How to add more citation styles to your installed styles