FOSS Linux published a tutorial about how to use Ctrl+Alt+Del to launch Task Manager on Ubuntu.
How to use Ctrl+Alt+Del to launch Task Manager on Ubuntu
Are you used to launching the task manager by pressing CTRL+ALT+DEL on a Windows PC? Here is how to assign the CTRL+ALT+DEL keys to launch the System Monitor.
How to use Ctrl+Alt+Del to launch Task Manager on Ubuntu