No need for laughs, we were all beginners at some point. In fact, i didn't do pull-offs correctly for aaaaages.
This kind of lick will eventually be a kind of reflex for you if you practise it for a while- its quite a common little pattern.
Use the index finger for the 2, middle finger for the 3 and your pinky for the 5 (thats fingers 1 2 and 4 if you like to look at it that way).
Start with your fingers in that position^^, while fretting with your middle finger- pick your first note then make the next note sound with your pinky without picking. (this wont take too much finger pressure to sound accurately, especially if you keep your left hand in a "good" legato playing position*). Next, to get from the 5 to the 3 you need to "pull off" the note to sound the pre-fretted 3**. The pull off is not just the opposite of a hammer on, simply lifting it up wont make the 3 sound well enough- when releasing the 5 give it a slight pull towards the ground before releasing (this will make the 3 sound much better).
Next from 3 to 2 you need to perform the same pull off towards the ground *** this time from your middle to index finger, then your final 3 is hammered on, again use enough pressure to make it sound but a good hand position will help alot here.
*a good hand position would be to have the thumb in the middle of the back of the neck, Pavel has a great example of hand positioning http://www.guitarmasterclass.net/solo-guit...o-etude-lesson/
**your middle finger should still have been fretting the 3!
***the pull towards the ground shouldnt be too much that it makes a change in pitch (due to the bending of the string) and should be the same tonw/volume as your hammer-ons
Hope that is of some help!