star wars - Where were the Knights of Ren during the events of The Force Awakens?

As far as I know:

we only see them in one brief flashback.

.

Did they play any significant role off camera, or in a deleted scene perhaps?

Are they even still alive?

Answer

At the end of the film, Supreme Leader Snoke instructs General Hux to find and return Kylo Ren so that Kylo

"...can complete his training."

Earlier in the film, Snoke calls Kylo the

"...Master of the Knights of Ren."

If Kylo still needs training and he is in command of the Knights of Ren, it is logical to conclude that the rest of them are also in training during the film's events.