it should have been already installed
type in a terminal
cd .node-red
npm install node-red-node-serialport
or
npm i node-red-node-serialport
sudo reboot
https://flows.nodered.org/node/node-red-node-serialport
or on nodered page http://10.10.10.1:1880 top right options button manage palette install tab search serial .. install
type in a terminal
cd .node-red
npm install node-red-node-serialport
or
npm i node-red-node-serialport
sudo reboot
https://flows.nodered.org/node/node-red-node-serialport
or on nodered page http://10.10.10.1:1880 top right options button manage palette install tab search serial .. install