DataTemplateSelector Xamarin.Forms

Hi, can anybody explain how can i create a TemplateSelector for a ListView?I want to have different views on each cell,depending on the content to load.
I found this article: https://oren.codes/2014/12/31/datatemplateselector-for-xamarin-forms/ which is amazing,but it doesn´t actually explain how to use it without Xaml. Suggestions or a way to use this templateselector with code would be awesome Thanks in advance