Welcome to the Disboards!!
First you download the graphics by right-clicking on it to save. Then search in your photos folder to open it. I usually do a 'dry' run with printer settings on fast draft just to see how it will turn out. If I'm happy with how it looks on paper, I set my printer to normal quality, remove the regular paper from my printer and have it print on magnetic paper.
I have also bought in bulk when I had 6 doors to decorate:
quality is ok, just a smidge less than the Avery.
Can also buy at Staples, etc.