Link Assets button disappeared from Shots View

In one of our previous projects, when artists opened a shot, followed by clicking in the Assets tab, they were able to see the Link Asset button in order to link assets to that shot.

Recently we’ve created a new project but by following the same process, the button is nowhere to be found as you can see in the images (old project / new project):


What are the steps required to enable this button so that artists can link assets from the shot view? Thank you so much!