Does teff flour destroy gluten, and what do do about it?
Teff is probably one of the oldest domesticated plants so doesn't lend itself well for modern processing: 


Normally the seeds are boiled just like rice
If you insist on making bread with it, you can make Injera (an unleavened bread)
For baking a "standard loaf of bread", it's not really suitable for that due to its high protein and mineral content, but you can still generously dust your bread with teff as you're using a small % anyway