Material greyed out in V-Ray Asset Editor

I’m sorry for such a basic question. I know the solution is probably very simple, but other avenues have not been fruitful…

…but I just started using a trial version of V-Ray 5 for Rhino 6 (I’m using Windows 10 in case that’s relevant) and I cannot make use of the “Material” tab in the V-Ray Asset Editor. It, as well as Render Elements, are greyed out – see attached screenshot. I can click on them, and a drop-down menu appears, but all the icons in that dropdown menu are also greyed out, and nothing happens when I click on them.

I am trying to do a very basic thing, just create a few basic materials to apply to my model. In previous versions of V-Ray you would edit and apply materials in the Materials Editor, but it’s been a while since I’ve used V-Ray and I guess I’ve lost touch! It’s so frustrating, I feel like I’m missing something very simple, but until I figure it out I can’t work with materials at all. Any help appreciated :frowning: