I assume you'll be doing this freehand, right? You need a very course benchstone. I've used a DMT extra course (220 grit), but even courser is better. Pick the angle you want, raise the spine of the blade until you get that angle, then use edge leading strokes on the stone until you raise a burr along the entire edge of the side not touching the stone. Flip it over and repeat on the other side. Remove the resulting burr with light strokes at a slightly higher angle, finish with progressively finer stones, removing the burr each time you change stones and when you finish. For an easy to maintain edge, create a micro bevel with a few light strokes per side on a fine stone at a higher angle (spine raised a little more).
There's a lot more details I could add, but that's it in a nutshell.