In Content Manager, use the filters to view missing dependencies. By default, the Faulty filter does that, but you can customize that to only show missing dependencies as I have to cut out the clutter. Once you see the EK3 listed, right-click on that and choose Download.
Download will check the DLS for any missing assets and install them. In this instance, there are going to be assets that will need to be installed from CDP files as well.
John
Trainz User Since: 12-2003
Trainz User ID: 124863
TRS2019/Trainz-PLUS: 114800
TRS22 Beta tester