When I downloaded the flashcards, I found them unhelpful for me, but that's because of how I personally learn. I think it really depends on the person - some people need to write their own because the actual writing engrains the idea into their heads while others can simply use repetition to hold information.

I would use the cards as a baseline. Go through them, pick out the cards you understand and separate out the ones you don't - depending on where you are at in your studies some of the ideas may be too complex while others you've already learned. As you progress in your studies, create your own cards and add to the pile that you understand. At the same time, revisit the pile that you originally didn't understand and see which ones you now understand. For those ones, add them into your growing pile. This way you save time from writing the same ideas, give yourself a path of progression in learning ideas, and build on your own base of understanding (with your own specialized cards).

Hope that works!

Ideally you should make your own flashcards, & make sure that you've covered all topics studied in GMAT syllabus.

You can use Eric's template.