By default, the manufacturer uses IP addresses such as 192.168.0.1 or the 192.168.1.1. Next, you should set a local IP address for the router. You can choose to go ahead with the setup wizard to configure the router or stick to manual configuration. You should see the option in the Administration section.
You should consider this mandatory as routers usually have a common username and password and anyone can easily get in.
Once you are logged in, change the password.
Change the default IP address and set the DHCP accordingly
