how do i download just the microsoft word?

Probably you won't, as it is part of Microsoft Office for Mac (or Office for Windows)

See a similar post, with links to MS site... in an ASC discussion:

https://discussions.apple.com/thread/5804990

Or there is an 'office-like' application for free:

http://www.neooffice.org/neojava/en/index.php

Good luck & happy computing! 🙂