On the bottom is a 4S that you had. The blue cell is the one you took out. So you need to re arrange the wires like in the pic on top. You can either cut, grind away the part of the PCB that is not needed. And you can either use a new 3S balance tab or cut away the part of your 4S tab to transform it to a 3S tab. It won't be a real 3S tab but it will still hook up to your charger with no problems. I don't think I need to say this but I'll do it anyway, whatever you cut, grind or whatever, don't cut too deep, don't grind too far and most important, don't short anything. Don't do anything if you're in a hurry, you have to take your time and be aware of where your metal tools are and where you put them.
What I mentioned above is stuff I did myself to transform two sets of 4S packs to 3S ones.