When you get a new router, there are a few things you can do to make sure it's set up securely.
The first thing you'll do is connect it to your computer and check the manual to find out how to configure it.
Once it's connected to your computer, you'll use the browser to navigate to a special address as instructed in the manual. It should be something like 192.168.1.1. This will take you to the login screen for the router.