Hi Johny513,
Squid rig is pretty simple. It is like high and low rig for porgy. You attach Yozuri squid jig instead of hook and drop to the bottom and move up and down slowly. If you feel any extra weight, just lift the rod and reel in. The Greenport pier is usually very crowded. If you have a boat nearby you have a definite advantage. Several years ago I discussed with Capt. Mike of Prime Time II for night squid fishing on his boat, but it never materialized.
Squid run in Greenport area doesn't last long, at most 3-4 week, so does jumbo fluke run which follow squid. Actually you can see school of squid on your fish finder. I suggest you try near Greenport pier area first. Squid usually bite better at night with the exception of Hyannis, MA where daytime fishing is as good as nighttime fishing. We made an exploratory trip yesterday morning on Rosie S in Hyannis, MA and found big school of squid are already in by catching 300-400 squid per person on squid jig.
Also I have a report that squid run near Newport, RI has started.