There are only 3-step, You Can Follow the steps
Number 1: you choose a second router and the router needs to connect your laptop or desktop PC or any device. and you need to go to the router dashboard. Here is everything firstly you net change the default or old wifi user password, New save it. remember do not restart your router because when you finish everything then me you don’t restart your router.
Number 2: go to DHCP setting / DHCP server,( here default have enabled) you do disable it.
Number 3: Go to the network menu Find LAN from there and change your IP address. because you need to be different from IP, you change the last number of the IP address example 123 or anything, you save this.
Finally, you find a notice for forest at your router, and you reset the router.