I want to set up OpenDNS.

I fillow instructions similar to those on this page:

Setting up tp link Archer VR1600v for OpenDNS - Home Network Community

In short, click on Network, LAN settings, then in the DHCP server section, enter:

Primary DNS (Optional): 208.67.222.123

Secondary DNS (Optional): 208.67.220.123

However, when I enter the Primary and Secondary DNS addresses, and click save, nothing happens--the router just stays on the same values displayed in Status:

Primary DNS: 220.233.0.3

Secondary DNS: 220.233.0.4

How do I get the router to actually update? What am I missing?

I tried rebooting the router, but that did not change anything.