I've spent a long time on this being led in circles. The online help tells me that to download the app is easy: I just download the app and sign in!
Things I have tried: I searched 'devices' but it just lists my current devices. I see no option to download the app. I clicked on 'how to download the app' with the above result: it just tells you what to do when you already have it.
I tried logging out of my account, deleting cookies then tried to select a movie to watch. Well you can't, you can only open a new membership and pay again.
So, where specifically do I download the Now TV app for pc?
Have a nosy at these links.