In the vast majority of cases, you will be using the router provided by your ISP and will not need to manage it directly unless you know exactly what you are doing. However I recommend you make at least one change: change the password of the admin page so nobody in your home can temper with the settings.
In the case of the Telstra router above, go to http://192.168.0.1 and log in with admin, password Telstra (this info is not secret). Then go to User Settings to change the admin password and write it down in your password manager
If you choose to purchase your own router, I assume you know how to configure it as required and cannot provide any further advice. You will need to refer to the documentation of your router. Please refer to the Wifi section to better understand your options if the Wifi provided by your standard router is not adequate for your house.
Note: you should reboot your router weekly to make sure that your device runs optimally. You can usually configure this in the admin page. A nightly reboot won’t update anyone in your house.
