I tried to install visual studio 2022 preview 17.1 and create new .net Maui project but it is not a single project and when I add a new page it is still Xamarin forms page and also have an error

I tried to install visual studio 2022 preview 17.1 and create new .net Maui project but it is not a single project and when I add a new page it is still Xamarin forms page and also have an error

It looks like you somehow have old templates. Open up a command-line window and run dotnet new --install Microsoft.Maui.Templates that should update you to the last ones, including the single project.