Jeff asks: "What specifically was said, and why is it a lie?"
Here some answers for ya, Jeff:
https://www.nytimes.com/interactive/2017/06/23/opinion/trumps-lies.html
And on taxes: https://krugman.blogs.nytimes.com/2017/10/14/lies-lies-lies-lies-lies-lies-lies-lies-lies-lies/
One more: https://www.nytimes.com/2017/09/25/opinion/columnists/republican-lies-krugman.html

There are lots more, but these should get you started. Of course, you won't read any of these because you can't handle the truth or you're just too lazy.

Best,

RTD