This is a short video that shows an excerpt of the work I do in the soldering lab. You can see a sped-up version of my process of preparing a Wemos D1 mini shield to work as an Electric Conductivity Node in my network.
I solder the header pins on the board and then solder a resistor and two cables of the probe to a prototyping board.
My github repository contains code and schematics of the node.