Ohhhhh poor girl, buddy, its all about speed, but the process is one of learning
Try keep some basic emergency tools on hand as when a snap happens its greatly depends on speed at which you can stop the air from contacting the innards of the stem, I put a small amount of rooting paste or vaseline, even honey is good, then quickly wrap a small piece of waterproof tape around the break and make it fairly snug as you want the branch to be close to its original form as it can be. Duct tape works well too just try not to connect the two end of the sticky together to create an unbreakable bond. If done correctly the duct tape will just fall off a week or 2 later once the knuckle forms.
as long as a tiny piece is still connected it will survive, although forever compromised, If its during flower id probably just chop it off and divert the energy it would have received to other branches. Good luck.