Now that your battery is secured onto the PCB with the cable tie, turn the PCB over and start soldering the battery terminals onto the PCB.

After the solder joints have cooled down, cut down the excess part of the battery terminals with a wire cutter.

Be careful not to make a short-circuit with the wire cutter or with the terminal wire that will fall off after it will be cut down.

Make sure not to touch the upper part of the PCB or the geiger tube, because these parts of the device are under high voltage.