The type or namespace name 'Gms' does not exist in the namespace 'Android'

"(are you missing an assembly reference?)"

I'm a long time Java/Android developer trying now to get a mapping app working in Xamarin. I found the following post which seems to be on point, but didn't help me:

https://forums.xamarin.com/discussion/6777/google-map-v2-didnt-find-class-com-google-android-gms-maps-mapfragment

I have the "Google Play Services" SDK installed. I have added a component "Google Play Services - Maps", yet i cannot compile my Map activity because of the following:

**
using Android.Gms.Maps;
using Android.Gms.Maps.Model;
**
looking at the samples i see under "References": Xamarin.GooglePlayServices.Base, Xamarin.GooglePlayServices.Basement, Xamarin.GooglePlayServices.Maps. How did they get there??? since i have a component (which the sample does NOT have...do i need these References?

help!!!!