How do I block ads on YouTube?

I am using combination of pihole (port#53) & unbound (port#5353) on my raspberry. Pihole upstream DNS is unbound Port#5353

I checked the pihole logs. Youtube URL are in this format

“r5---sn-uxa0n-ttze.gvt1.com”

“r3---sn-uxa0n-ttjse.gvt1.com”

In these type of url’s “sn-uxa0n” always there & other contents change every time.

If youtube urls are city location based. Then with unbound I think they come from central youtube server, so this method can help everyone who using unbound as upstream DNS

Is some body help me how this method is implement for this type of url. thanks