can anybody give me a step by step run down of how to slice a psd or png image created in the gimp with graphic convertor. i have no idea what to do other than select the boxes i want as slices.
That's pretty much all you need to do, make the boxes and fill in the names.
Save in the original format in case you want to adjust the slices later.
To make a usable page, use File->Save As… and pick "Slices (*.HTML)" as the format. This will generate the HTML page and make a folder full of the slices.