Can someone tell me if I am missing something. In the new RC app, How do I assign a name to a phone number?? This seems very basic.

You cannot.  It's been a request for 2+ years, and yes, it's very basic.  
Apparently, you can do it on the mobile app, but not the desktop.
If you search this forum, there is an incredible community of people who are as frustrated as you are about this.  It's crazy.
Sorry to be the bearer of bad news.

Hello!

On the new RC App, there is no option yet. But RingCentral is already planning for this and will soon add it. Vote for this feature request here.

Thanks!

There is no address book for the Glip app. It does not sync contacts with anything. You are not missing anything.