I have made an updated version of this video that is more clear to understand. See it here: https://youtu.be/vMXSH4SRIuA
Please note that this won’t work for all routers. It will work on most Linksys routers, which, in my opinion, are the best you can get.
This video will show you how to use your older wireless router in conjunction with your new router (via a long ethernet cord to another part of your house) to boost your network’s wireless signal throughout your house. Note: You will have to end up with 2 different wireless networks BUT they are both on the same internet network for you to use for internet access. You will need to connect them via a long Ethernet cable from a client port on the first one to a client port on the second router. The 2nd router’s DHCP server will need to be turned off as the first router will be assigning local IP addresses and the second router MUST have the option to change from “gateway” to “router”, or a similar option, for this to work. On a standard linksys admin or configuration page, it is under “advanced routing”.
PS: I’m sorry about the quality of this video/details left out. I put it together really fast. Some details are in the annotations. I also didn’t expect this to get this many views.