[Linking a video to a mod]

Hi, when I add a video I cannot seem to link it to the featured mod.

In the publishing option it says:

 

Featured mods If your video is showcasing files that can be found on the Nexus, please add them below.

 

What do I put for this option? I have tried the url for the main page of the mod and also the name of the mod, but neither worked.

Can someone help?

 

thx