when you login router management page(192.168.1.1), you will see basic on the top--wireless---change the name and password there.
about how to login, refer to this.
http://www.tp-link.com/in/faq-114.html

Thank you for your kind response. I did make the necessary changes to the network names. I have another question.
This router has two frequencies (2.4 GHz & 5 GHz). When both are active, does it make any difference by using any of them for any specific device ? The TPLink sales guy mentioned to me that 5 GHz is more suitable for all Apple devices (Macbook laptops, iPhones, iPads etc) since 5 MHz will be much faster on Apple products. We use only apple devices and I could not find any difference in speed or in any action when I use 2.4 or 5 GHz. Infant the 2.4 GHz gives better range signal and I can work from any corner of the house whereas the 5 GHz does not work in that same location. Can you pls explain the advantage or disadvantage of these two frequencies ? Thanks. badri

see here, https://www.speedguide.net/faq/is-5ghz-wireless-better-than-24ghz-340