Hi
You're almost there, don't give up
You have used just one letter too many: gufw instead of ufw, therefore mixing up the command line tool ufw with the GUI tool gufw. Gufw is just the graphical frontend for ufw, just to make your life more clickable
So what you did by typing in "sudo gufw enable" is NOT enabling the firewall straight away. The "enable" part in that command is not processed. You just started gufw with root permissions, like only typing in "sudo gufw". You then need to make sure to switch the status, so that it looks like this:
Or, if you want to enable it on the command line, this is the correct command:
sudo ufw enable
Both is starting the firewall and setting it to autostart when you boot up the system. Gufw is only the tool to configure/manage your firewall, you don't need to autostart gufw.
To check that your firewall is actually running, for example after reboot, either check the status in gufw (see image above).
Or use this command:
sudo ufw status
Hope it's more clear now what I was talking about
Let us know how it goes...