How to get Pihole to start blocking ads

I'm a welder, I don't even know what a DNS is lol. I'm sorry, I know this is probably very frustrating for you trying to explain this all to me. That was what the DNS was set to on the Pihole instructions here:

Like I said, I really have no idea what I'm doing here, so it's probably something very simple I missed or messed up. I just assumed that was a set number for the DNS. I'll change that when I get home from work and hopefully that fixes everything.