www.megadrum.info

Hello. I would like to know what I wiring have to change and resolder to make Yamaha's hihat RH-135 work properly.
Here's the photo, as looking megadrum left to right hand

https://ibb.co/m6nVyGX

MegaDrum as standard comes with Roland type HiHat wiring. For Yamaha HiHat controller you need to use a crossover cable (tip->ring, ring->tip). Or, if you want to do it in the module, swap tip and ring wires on the HiHat controller jack.

Can you please give me a picture of what wires to swap on the module using the image I've uploaded? Otherwise draw me a diagram

I don't have a picture. I'm don't quite understand what is causing the confusion. A normal stereo cable has straight connections for both signals (left and right). That is a tip from one end of the cable to a tip of another end of the cable, a ring from one end of a cable to a ring of another end of the cable.
A crossover swaps tip and ring wire at one end of the cable so wires kinda "cross" each other, so this is why I call it a crossover.
If you do it in the module you swap wires between tip and ring, effectively doing the same as with a crossover cable. But in this case with HiHat controllers which use Roland wiring you will have to use a crossover cable (or swap tip and ring the in the module again).