Here are the five things you need to do with a new router ...
1. Change the SSID and the default password.
2. Turn off WAN Administration (this allows administering the router from the outside)
3. Turn off Universal Plug n Play (UPnP)
4. Turn off WPS WiFi Protected Setup (one button log in)
5. Turn on Encryption and select WPA3 or WPA2. Do NOT use WEP. It's not secure.