If you don't set the DNS addresses in the router or in your pc/laptop/mobile device, then the router will use the Rogers DNS addresses as supplied by the CMTS. The connected devices will then use those same addresses. So, you really don't have to do anything unless you want to use another DNS such as Google, OpenDNS, Quad9, etc.
Just to note, from Ottawa, there is a difference in response times for the IPV4 Domain Name Servers. 184.108.40.206 provides a response of about 15 ms, while the 220.127.116.11 response time is about 30 ms. If you want to clock the response times, so that you know which one is faster from your location, take a look at the following post: