This is a prototype project application development of animal blood donation in a xamarin.forms application.
The Xamarin.Forms NuGet packages are not part of these projects. They must be downloaded for each project.
To avoid hassles, download the NuGet packages for the solutions in the Libraries directory first. You'll want to load each library solutions into Visual Studio, right-click the solution name in the Solution List and select Manage NuGet Packages for Solution. A notice might appear at the top of the Manage NuGet Packages dialog that says "Some NuGet packages are missing from this solution. Click to restore from you online package sources." If so, click the Restore button and then the Close button. Build the library.
Do the same thing with the other library solutions in the Libraries directory.
You can then load any of the application projects. For each project, again right-click the solution name, select Manage NuGet Packages for Solution and go through the same process.