I just finished sorting this out, hope this helps you. The antenna is almost always destroyed by removing the digitizer so plan on replacing it. It is a very inexpensive part so order it at the same time. One end attaches to the underside of the MB but can be accessed without removing the MB by removing the top shield and popping up the wireless board.
Here is what happened to me: I attached the antenna connector to the silver post and re-assembled. The wireless signal was dead awful but available if you set the iPad next to the router so I knew all the electronics were OK. Then I disassembled again, placed a piece of tape over the antenna connector at the post on the wireless board to make sure the connector does NOT touch the underside of the metal MB bracket! There is practically no room to avoid shorting the antenna post otherwise. Even though the antenna wire eventually makes contact with the metal case it must travel through the antenna first (I guess to tune the frequency better).