+--------+                   +--------+
 |  Main  |    connects to    |  old   |
 | Router |<------------------|Notebook|
 +--------+     Main wifi     +---.----+
                                 /|
                                  |plugged in
                                  |by cable
                                  |("internet" port)
+---------+                   +----------+
| gaming  |    connect to     |  local   |
| devices |------------------>|  Router  |
+---------+    local wifi     +----------+

-Log into your old router

-Configure your old router to be a unique SSID

-Disable DHCP of the old router

-Connect Port 1 of your old router into port 1 of your new router