I cant understand how to select a reference image and install it into my active Krita 4.2.8 illustration, I can open or copy a potential reference image from my photo files. but neither the "Paste as Reference Image" button or the small icons floating above the tool options seem to do anything. I also notice that there is a push-pin icon that has something to do with reference images. I am using Win 10 on a desktop.
I just can't seem to link this all together. I would greatly appreciate a small step-by step on how apply and manage reference images. Thank you very much.

When you click on the Reference Images Tool icon (the push-pin), the Tool Options docker then has all the controls and options for dealing with reference images. Also, any reference images then become 'live' and can be selected by clicking on them, moved, scaled, rotated and deleted (Del key) as required.
A look at those controls and options should give you a good idea of what is possible and how to manage reference images.

If I do Paste As Reference after copying a layer in another document, I get the pasted layer content floating as a reference image over the workspace. I can do more like that and have them embedded (see Tool Options) into my saved .kra file.
The '+' icon is used to select an image file and have its contents added as a reference image.

Sincere thanks for your very helpful reply.
Greg