You can either change the DNS in your router settings, so all devices that connect to it automatically use open DNS, blocking adult, phishing and anonymity websites.
Or change to open DNS in one or more devices directly, so you will be blocking adult websites with only the the device/s you chose to use it on.
This will not stop all unwanted content or viruses, but will block all known websites that have adult or unsuitable content. So please be careful what you click on, and email attachments that you open.
Log onto you router by entering 192.168.1.1 into your search tool-bar, then enter your admin user name and password, usually admin, admin or admin, password. Then go to DNS settings, usually under advanced or dynamic DNS settings, then replace the primary and secondary DNS servers with.
Then save your settings, reboot your router and check to make sure adult sites are blocked.
go to settings/control panel, then network settings, then replace the DNS servers with the ones above, then save your settings, reboot and check adult content is blocked.
The single PC option is great for a children's PC.
More router security settings can be found here.