It appears Centennial is going in like a FWH in a 60 minute boil.
With 30 minutes left you are adding Willamette, Amarillo and Centennial.
With 15 minutes left you add Cascade and apparently turn off the heat at this point at let it sit (flameout).
^this is what they mean. I would suggest taking your directions from Palmer's book instead of that write up though. (See below for some other changes) I would suggest maybe adding the extract towards the end of the boil (<15min left) to avoid burning the sugars and limit the mailiard reactions which can darken your beer.
the directions continue as (changes suggested made in
bold
Allow mixture to cool if necessary
ITS NECESSARY!!! , until under 90 deg F.
under 70degrees
§ If you wish to take a hydrometer reading for starting gravity, do so now. Gravity ranges for this kit are listed on the front of these instructions. Sprinkle the yeast over the mixture, wait 10 minutes and stir gently with 1 or 2 spoon strokes.
Please take a gravity reading. It will help you learn to use your equipment and helps you remake recipes later
§ Taking the airlock in one hand, and the lid of the fermenter in the other, gently twist the airlock tip into the hole of the lid. Place the lid on the fermenter, and push down hard until the lid is tight. Finally, fill the airlock half full of water and cap.
I'd fill it with starsan or vodka. This helps prevent infection in the rare case of "suck back": when the fluid in your airlock gets pulled into your fermenter due to pressure changes. This is unlikely.
§ Over the next 24 hours fermentation should begin, and youll see bubbling through the airlock. Fermentation should continue for 48-72 hours, and then cease as settling begins.
fermentation could take up to 72 hours to start. Bubbling does NOT indicate fermentation. Please please please, do not rely on the airlock as a fermentation gauge. All the airlock does is let CO2 escape, and keep O2 out. It is a valve only. If there is a leak/poor seal on your fermenter, the airlock may not bubble, yet fermentation WILL occur. Also, fermentation takes as long as it takes. This may be 2-3 days but more likely will be 2-3 WEEKS! keep reading please...
§ 3 days after fermentation has begun, open the lid of the bucket and dry hop the beer by adding 1 oz each of the Amarillo and Cascade hops. Replace lid and airlock.
wait 2 weeks before opening your beer. At this point, the majority of your fermentation will likely be completed. Take a gravity reading with your hydrometer. Close up your fermenter. Then wait 2 more days. Then take another reading. If it is the same as before, then add your dryhops and close the fermenter back up with the lid and airlock. If it is lower than before, wait 2 more days and recheck.
Bottle 7 days after dry-hopping.
This step is good
Sorry for the long response here, but hopefully my suggestions will help make better beer the first time. Also very important, keep your fermenter in a cool place so the fermentation temp doesn't get too warm. Best bet is around 60*F for the first few days.
Read lots on this forum, and continue to ask good questions. People on here are here to help and are full of great information to help you make delicous beer. Good luck!