Breathing and kegel exercises

In preparation for an upcoming prostate surgery within weeks, I have pro-actively started kegel exercises to minmize the impact and duration of incontinence post-surgery. Different instruction videos on the subject have contradictory instructions on the breathing aspect while doing the exercises. Many say, breath out, hold your breath and tighten the pelvic floor muscles. Others instruct, continue to breath normally while tightening the pelvic florr muscles (which is very diffcult to do). What is the right approach?