Put the branch in place as it should be and then tape it with some paper tape (a bit loosen, don't choke it). Alternatively, you can take a metal wire and wrap it gently around the broken branch to support it. In few days it should be healed. Keep an eye on the "medication" since you don't want to let it become too tight. When it's completely healed you can remove the tape/wire.
I broke a branch (not completely) when my auto was already flowering and in 2 days it was brand new again :) they really are amazing plants