Although the GUFW GUI may seem deceptively simple, the graphical front end is both easy to use and capable of performing the most common firewall configuration options. The graphical tool is a perfect place to start if you find ufw and iptables overwhelming. More here

Again the most difficult part of managing a firewall is knowing who you wish to allow or restrict (by ip address) and what service and port you need to allow (open) or deny (close). Gufw can help as many of these options are preconfigured. If you need further assistance, start with gufw, configure as much as you can, and then review the other two links.