First of all, I have tried without install Elementary OS on my computer.
I have seen that when I click on Applications and I click with right button the application that I would like to uninstall, well it doesn't work on all the software. For example, I have tried to uninstall Epiphany, but the button "Uninstall" it wasn't show. So how is possible to uninstall apps ?
Second. Which is the firewall that I should use ? The native firewall in settings or should I install gufw ?