Moved into a new flat, don't know how to set up the router

I moved into a new flat in Whitechapel last month and the internet provider sent me a router but I don't know how to set it up. There's a socket in the living room I think is the master socket, and the router is still in its box. I do not have a desktop, just a phone and a laptop. I'm working from home two days a week and need this done fairly urgently. Looking for someone who can come in the next week or so, set it up, and ideally help me change the WiFi name and password from the default. Should be a quick job for someone who knows what they're doing.