Orbi RBR50 White flashing light

Your modem already has a built in router and wifi. This would be a double NAT condition which isn't recommended. https://kb.netgear.com/30186/What-is-Double-NAT
https://kb.netgear.com/30187/How-to-fix-issues-with-Double-NAT
Couple of options,
1. Configure the modem for transparent bridge or modem only mode. Then use the Orbi router in router mode. You'll need to contact the ISP for help and information in regards to the modem being bridged correctly.
2. If you can't bridge the modem, disable ALL wifi radios on the modem, configure the modems DMZ/ExposedHost or IP Pass-Through for the IP address the Orbi router gets from the modem. Then you can use the Orbi router in Router mode.
3. Or disable all wifi radios on the modem and connect the Orbi router to the modem, configure AP mode on the Orbi router. https://kb.netgear.com/31218/How-do-I-configure-my-Orbi-router-to-act-as-an-access-point and https://www.youtube.com/watch?v=H7LOcJ8GdDo&app=desktop 

I would check on getting the Modem into bridge mode if possible. 

Press the reset button on the back of the RBR for 15 seconds then release. The top ring LED should blink WHITE for about a minute, then it should change to slowly pulsating ON and OFF. Does this happen? 

Just connect the laptop to the RBR using the ethernet connection temporarily while you attempt to get the RBR setup. Let us now if you can access the RBRs web page at 192.168.1.1 using the wire connected laptop. You'll eventually get the laptop connected via wireless, if we can get the RBR setup correctly or determine if the RBR is fautly.