The List Picker is an alternitive to the built in Umbraco list data types of dropdowns, checkboxes and radio button lists. This data type differs in that it allows you to select a dropdown, checkbox or radio button list then add the item to the list with display text and a value and finally a way to set an item (multiple items for the checkbox list) as a default value.
Download packa and install via the Developer seciotn in the Umbraco back office, done.
Install with Nuget (https://www.nuget.org/packages/DtpListPicker.Umbraco):
Use the List Pick as you would any other property from a content page. There are NO special class the need to be referenced in your view. Examples: