Animated GIF (Movie) in PhotoPaint

What little help I can find online indicates that I should be able to create a new document in PhotoPaint 2017 with the option for a movie by setting the number of frames at file creation time. However, the "Number of Frames" option in the "Create a New Image" dialog is grayed out.

I created a new document and imported my four .png files for the animation. When I open the Movie dialog & toolbar, I can't do anything with the images. If I initiate the creation of a movie, I can't figure out how to get my images into the frames. 

Precious little on this online, and it apparently doesn't operate as it used to in X4 & X7.

Does it work? Am I doing it wrong?

Thanks for any help!