Electrical – Wiring 3 way switches

I am thoroughly confused on this and looking for a wire diagram or some advice. My father in law was trying to replace a switch that cracked and after attempting to install it and the lights not working he called me. I showed up to wires pulled out and no clue of how it was previously wired before when it was working. The situation is that there is two separate three way switches powering about 8 or 9 flood lights in his living room. Both switches have their own power source running into their gang box. The best I have gotten so far is getting one switch to basically be the “master switch”. This switch works in the on and off position. When the switch is in the on position the other switch will work but when the “master switch” is in the off position the other switch has no control. Looking for help. Thanks