After adding all of the pages with the help of the extension, this error appears.
Severity Code Description Project File Line Suppression State
Error You need to add a reference to Mono.Android.Export.dll when you use ExportAttribute or ExportFieldAttribute. Test.Android C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets 2067
The resolution is to add dll manually as explained at stackoverflow.com/a/31085646
References -> Add Reference -> Mono.Android.Export
Thank you for your efforts.