Shoulda coulda woulda

This question will reveal to all the low level of my shorthand skills, but here goes:  in what Gregg book, if any, are contractions dealt with?  "Wouldn't have; didn't like; should've gone; she'll know; we're here" etc.  I don't seem to find the issue addressed per se in the early books, and maybe I don't have enough of the post-Simplified books to have found the you just put an apostrophe over the letter, or write it as it sounds with "nt" "l" or "v" or what is the basic principle?  Thank you...I had such good luck with my first question, I though I'd risk I pressing my luck?!  

(by jim for everyone)