Rg Plugins Popup with Xamarin Forms not working for shared project

Hello,

I am very new to xamarin. wanted to show Page popup(not full screen) in my shared project(IOS and Android).
after research i came across Rg.Plugins Popup.

i added nuget package to my project, i am trying to use it but Demo does not work properly asking for some pakages to installed i do not have any idea which one.

i tried to initialize for respected platforms but Rg.Plugins.Popup.Popup.Init(); Init not available....

is there any proper sample code or project to check how to use Rg.Plugins Popup?

Please Help