This application note describes how to install the WL-MIO Node-RED library.
Follow the steps in https://wlmio.com/apnotes/wlmioan30000.html
Install npm and libgpiod:
sudo apt install npm libgpiod-dev
Start Node-RED from RasPiMenu -> Programming -> Node-RED
Open a web browser on the RPi and go to http://localhost:1880
Click on the hamburger menu in the top-right and then select Manage Palette
On the install tab search for: wlmio
Install the node-red-contrib-wlmio package
Once the Node-RED package is installed, you are ready to start creating flows!