If for the 15b17b15p13
It applies the same with the method described by guitarplayer. You bent the note whole step up then bend it down back to the original. Means ur makin the note goes from 15 up to 17 then back down to 15. All with a single strum

...p13
Thts a pull-off from the previous note. So get urself to do this:
position ur 4th finger on the 15th fret,make the bend (15b17b15),position ur index finger to press on the 13th fret.as soon as u have bent back to the 15th fret...just make the pull-off

Do check out the lessons and videos regarding bout pull-offs to get the idea of it.
=)