newbie question: how to use TIFF in GIMP

well, in my rambling sort of way, i believe that’s what i did…when first opening the tiff i had the option to open as layers or images…i chose images, (as the layers option alway has that small image in the left top corner) - and the tiff image is now saved in xcf format…but i understand in the end it will be saved as jpeg…just want to work on it as tiff first.