adding xliff to existing project

Question

Client sent me an xliff. A project was created when I clicked on (and opened) the xliff. 
 I now need to add a new xliff file to the project. 
 I've done this before, and as I recall it was fairly simple, so I don't know what the problem might be. Since I was unable to add the file, I duly looked for instructions. 
 Here: 
 https://gateway.rws.com/csm?id=kb_article_view&sysparm_article=KB0025756 
 I find: 
 
 Double click on your existing Project , this takes you to the Files view. 
 Now from the left choose the source language . 
 Right click anywhere on the white space on the right side where the existing files are. 
 In the right-click menu you have Add Files . 
 
 I see "Add Files," but it is grayed out. 
 What am I missing? 
 Thanks,

Paul · Answer

Alan Patrick Hynds Carr 
 Alan Patrick Hynds Carr said: A project was created when I clicked on (and opened) the xliff. 
 When you open the file this way you create what's known as a "Single file project". This is limited to only being able work on that file in the project. 
 In many ways it makes sense to use project templates more, and always create a "Studio Project" via the wizard. That way it's not only fast, but you extend yourself the ability to expand on the size of the project if necessary in the future.

Trados Studio > 1. Trados Studio

adding xliff to existing project