confuse how to configure 2 red interface

[Guest]

[mangthjik]

Dear sir... I have 2 modem router which is  Modem A ip 192.168.1.1  modem B with ip 192.168.1.2
so I configure the lan ip 192.168.1.15
but I am confuse with the red one . I fill eth 1  ip 192.168.1.3 with gateway 192.168.1.1
but where i should input the other ip eth 2 ? in the box list i fill 192.168.1.4/24 but where I should fill the gateway for 192.168.1.4 --> 192.168.1.2

help me please... thanks before...

[mangthjik]

I Find it.... so
just enter the first on then skip thinking other red ip .
configure next at  menu networking after all installation by adding other uplink .

[mrubs]

You should configure your modem one by one.