What that says is that you should grab the note on the 2nd fret. Then hammer on the 3rd fret briefly and then, while still holding the string down the 2nd fret, pluck the string with your freting finger as you release the 3rd fret.

This is MUCH more difficult to explain than to demo. I expect an instructor will show up soon and tell you where your can find a video that will demo the the lick.