This guide will show you how to run multiply planks on elementary OS. It can be rather useful if you have more than one monitor.
Open the terminal and copy/paste:
plank -n panel-two --preferences
In this example I use the word panel-two, but you can call it whatever you want. You can call them panel-one, panel-two, panel-three etc.
Now setup your new panel.
When done, go to System Settings. Click Applications and pick Startup.
Add the following command;
plank -n panel-two
Now log out and log in. You’ll now have an extra plank.
Tested on: elementary OS 5.1.4