@2BRicardou,

It is up to you how you go about upgrading your network, but as an example:

I would recommend replacing your current router with your new router and configuring your network as you want. If you are looking to continue using your older hardware as a method of extending your network, you would need to connect the older router and access it's settings to place it into AP (Access Point) mode. At this point, you could use the router to extend the network - as long as you are able to provide a wired connection to the AP.

If you are simply looking at removing the older router from the situation, I would recommend resetting the router and removing it from your account - especially if you are looking to recycle the router, but it is not required.