After reading the many posts, I installed the system as MODEM-OOMA-ROUTER. My internet kept dropping its signal multiple times a day. I constantly had to reboot OOMA and my MODEM. My understanding is that MODEM-OOMA-ROUTER is better than MODEM-ROUTER-OOMA because MODEM-OOMA-ROUTER allows OOMA to use "quality of voice" to ensure that priority goes to OOMA when the internet is used by multiple sources. It can control the minimum bandwidth that goes to OOMA. Well, all that seems logical but my internet kept dropping signals.
I found a couple of posts where a smart person mentioned that MODEM-OOMA-ROUTER is the configuration for the average computer system. But if you have good computer gear (I do, I even build my own computers as a hobby), you are better off using MODEM-ROUTER-OOMA. An advanced router (TP-Link 1043ND) will also allow you to control bandwidth. Armed with this information, I switched from MODEM-OOMA-ROUTER to MODEM-ROUTER-OOMA. I configured my router to allocated a minimum of 10% of my bandwidth to OOMA.
And Voila!! No more internet problems. I love my OOMA now. I am passing on this information just in case others are struggling as I did. I am glad that I did not return my OOMA before I gave this a try. Someone also mentioned that OOMA was never designed as an advanced router. So the MODEM-OOMA-ROUTER can give some people like me problems. It all makes sense to me now.