Use of "control" event and bitfield operators "levels" and "edges"

I am a slightly confused as to how to use the "levels" and "edges" which are the integer bitfield operators used in the control event. Can anyone point me in the right direction to show me what each of these means in the context of the user keys. For instance, if I wanted to make something respond when I press the "e" key, what is the appropriate settings for the "levels" and "edges" for the script to properly detect that?

Thanks in advance,
Apollo

lslwiki.net/lslwiki/wakka.php?wakka=control

(note, what are called "levels" and "edges" in the editor tooltips are called "held" and "change" on the above page, which make a little more sense)

Thank you Deanna. I wish the LSL Portal and that wiki were mirrors.

it's slowly being worked on (the LSL_Portal I mean) to be brought closer to being as informative.... anyone with an SL account can edit and help out, just be aware that you cannot copy from lslwiki to LSL_Portal without permission from the author of the copied material. I try to do a little each week, adding examples, linking functions to categories, and other little things... if you have 0 comprehension of how to do edits (like me at first) you can use your own user page as a practice area, and I'm more than willing to help with any questions, if I know the answer... my own user page is located @ https://wiki.secondlife.com/wiki/User:Void_Singer and there is a link to my talk page, feel free to leave questions there, I check every few days at worst