Your english is great, don't worry!
From what it sounds like, the wiring of lug 2 of the volume is not correct. It says 'output' on the layout cause it's the output of your circuit(board). Not because it has to be soldered to the output(jack).
I'm not sure what 3pdt switch wiring you are using, but let's take the Offboard section on this page as an example ( https://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html
). You can see there is a blue wire from the circuitboard going to the switch, and then a different grey wire going to the output jack.
Lug 2 from the volumepot is the same as the blue wire in this example. It's the last part of the circuit if you will. In the example the circuit ends at the board, in the pedal you're making it ends in the volume lug 2 (to simplify it).
So your wire from the volume pot should go to a different part on the 3dpt switch than the wire from the output jack does.
Hope im not making it more complicated, but what happens in truebypass when the switch is off: Your guitar goes from the input jack, through the switch to the output jack. There is nothing in between.
And then when you turn on the switch, that same guitar signal takes a detour. Instead of going direct from inputjack to output jack, the switch sends it from the inputjack through the green wire in the offboard example. It ends up in the circuitboard, which does all kinds of things with your signal, distort it whatever, you have knobs, switches etc etc, and at the end of all of that, there is that blue wire sending it back into the switch and then it goes from there to the output jack.
I don't think this is the only problem, but I would start there!