Well this is a little late for your test, but, for future reference - in general for electronic machines you need to position the printhead where you want the margin set then hit the appropriate mar. set key.
to move the printhead past where the mar. is set you need to hit the 'mar rel' key and use the spacebar or backspace key to position the printhead. some machines don't have a "mar rel" key and on these machines just using the space and back sp. keys will do it.