Here are step by step installation EndNotes for Windows 
Step 1: Download your preferred version of EndNote from here: For Windows. (recommended version X20
)

Step 1: Download your preferred version of EndNote from here: For Windows. (recommended version X20

There is some user getting an error during launching their Microsoft Word indicating unable to load an add-in.

The workaround is to open Word with Rosetta.

The workaround is to open Word with Rosetta.
- Install Rosetta
Run this command line in terminal/usr/sbin/softwareupdate --install-rosetta --agree-to-license
- Open Word with Resetta
- Quit EndNote and Word
- Open Finder > Application folder
- Right click Word icon > General tab >
Tick Open using Rosetta
- Open Microsoft Word, to check the previous error message.