Custom Search Results Display Template Download Link using Selected / Item ID

Hi All,

I would like to create a download link on a search results display template to this url:-

http://<sitecollection>/_layouts/15/Dladvopt.aspx?List={521EFD95-D9DE-401D-8EE4-A37959710E17}&SelectedIds={Selected / Item ID}&ViewUI=1

How can I get the selected item id to dynamically populate the SelectedIds variable?

Any help would be great and thanks in advance.