WiFi router?

Hi everyone, I hope someone can help me. I got my wifi router from o2 today and they sent me a text message saying that I can activate my connection without a technician, but the problem is that I can't get onto anschlussinfo.de because I don't have wifi, so the page doesn't even load, but I have to be connected to the wifi, which doesn't make any sense. I can get in with my hotspot, but I have to be connected to the wifi, how am I supposed to do that? I would be grateful for any help, thank you😄