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 ?
gufw is just ufw (uncomplicated fire wall) with a graphical interface. You get ufw already installed with elementary, it's just that the graphical interface is different, integrated in Settings. There are some Linux distros where ufw is installed without a graphical interface and you turn the firewall on in Terminal with sudo ufw enable.
Everything you do via App center you can do via command line
Linux Rules!!
sudo apt remove epiphany-browser
** if you would like to remove its dependencies the replace remove with autoremove, but it might remove needed depencies as well, so proceed with caution
but I think I've also found it in the app center, it's called "gnome web"
