How do I enable AdGuard Home in my router?

[ignfv]

Hi there, thanks in advance for your help. So I've been trying to install AdGuard Home on my router, but I haven't been able to yet. I've already installed it via Terminal, so I can access its settings via browser, but I don't know how to add it to my router. The guide says I have to find the DHCP/DNS settings in my router, then look for the DNS letters next to a field which allows two or three sets of numbers, each broken into four groups of one to three digits and add then enter my AdGuard Home server addresses there, but this info seems very vague... I see lots of options for DNS settings. I have no clue where to add the home address I have (I see only 1 in AdGuard Home: 127.0.0.1). Could you please help me with this? I do not use HomeAssistant/Docker/etc...

I own an ASUS RT-AC86U by the way.