Flexcut knives come nicely sharpened and you can keep them super sharp with strop and the compound that came with your knives. This is the strop I have. There are some a little cheaper, but this is a little longer (12") and has silicon carbide surface on the back to touch up dull spot.

I'd avoid getting a sharpening stone for now. You're much more likely to damage the blade than to put a good edge on the knife.