Are you doing
this kit? So aside from the can of liquid malt extract, it says to add either 1kg of their Brew Enhancer, or instead use 500g of Dry Malt and 250g of either dextrose (corn sugar) or sucrose (white sugar).
Dry malt extract is
better than sucrose or dextrose. It's pretty much dehydrated powdered wort (the liquid produced when mashing malted barley), so it's the closest analogue to what you use when brewing a beer in the traditional way from actual malted barley. You're asking to get rid of the dry malt extract and use strictly sucrose as an addition to the stuff in the can.
I would brew it as labelled, or get rid of the sucrose/dextrose completely and use only dry malt extract in addition to the can, as unionrdr suggested.