seeing my cameras thru my c3700 modem/router and the r6300 router

ok you helped me with that c7000 modem/router that i found was not compatible with comcast in my area go figure. anyway so once more i tried to get the r6300 router and the c3700 modem to connect together. well for now i managed to get them to connect. now i'm online using the c3700 as the modem and the r6300 as the router. and believe it or not i got 90 mbps with the r6300 online going thru that netgear switch at least for now anyway. so that c7000 was bad for me.

now i have a issue i need to get fixed or i will have to take the r6300 router offline, as i can now not see my cameras. i use a tablet that is wifi connected to the r6300 router for wifi access and the app will not show my cameras. if i connect the tablet to the modem's wifi i can see the cameras but the pourpos of thsi setup is so i can take the extenders of and have wifi out in the yard and better speed for the tablet. the app still want's to use the ip address that ip chicken gives me, that address is for the c3700 modem/router that is connecting me to the internet. i figure that is correct for the internet. but now my cameras are blocked.  also the modem now only sees a few devices and the router see's only 2 devices. so how do i get the router to get thru the modem so i can see my cameras? i tired inputting the routers ip address in the field the app uses for the internet  but the app keeps putting the modem address back. if i can't get this to work i will take the router back offline and see about getting a gigabit switch to see if i get faster speeds. but for now if i can get the tablet to see thru both router and modem it will make my day. i have port forwarded the cameras on both units.  thanks for any help