For this step you need access to your Ubuntu Linux cloud instance. When your cloud server is on Amazon Lightsail, you can use the Connect using SSH from the Connect tab from the Lightsail console and enter:
sudo apt update
sudo apt dist-upgrade
The apt command updates the packet information and the dist-upgrade runs the upgrade of the system. Especially when you have done this system upgrade initially or if a "reboot" is mentioned on the command line, do a reboot of your instance:
sudo reboot
Important: I recommend to do an package update and dist-upgrade quite frequently. I do it at least once a week (I create a snap shot from within the Amazon Lightsail console before and then keep it for one week, do the updates and delete the snap shot from the previous week) and, in addition, do the same before I begin working on the command line to install new programs and applications.
