The dallae will come wrapped in a rubber band. Don't take that off - makes it easier to prep in the next steps.
Use your finger and gently pop-off the hard stem ends from each of the bulbs (reference video). Be patient, as it may take a few minutes for this step.
Next, take-off the outer layer from each of the onion bulbs - only if it's loose and easy to peel. You can skip the ones don't come off easily.
Now, let's wash them. Take out a large mixing bowl and fill it with cold water. Shake the dallae around in the water - to get rid of excess dirt and any impurities.
Then give it another thorough wash under cold, running water. Shake-off any excess water.
Then use a few paper towels and pat-down the dallae to remove any leftover moisture (don't forget this step).
Now, use a knife and cut the dallae into small pieces (2~3cm).