When your old modem and router don't really work with WiFi, and you order new connection devices, it might be hard to configure the Internet connection. I used to have "belkin.31a4", the WiFi network I was used to. When a new modem and router came, it was hard to get the new network working up. (TP-LINK_4141D6)
Step 1: Turn WiFi on and off.
Step 2: Scan for available WiFi networks. While scanning, look under your new router for the network SSID.
Step 3: Connect to the new network. If it needs a password, that's under your router, too.