Ideas on how to convert a regular closet door into a "barn door" ?

We need every inch of space in our small bedrooms and would like to convert the bedroom door and the closet door of the master and the closet door of the spare bedroom into barn door style doors . But buying a pre made barn door is pricey and we would like to reuse the doors themselves but aren't quite sure if they need to be slightly wider than they are now and how to go about converting them for the task . the fixtures has been found at a reasonable price on amazon already . we haven't yet got the keys to the place ( waiting for closing ) yet so i don't have photos sorry