Terminology question from a n00b

I'm planning on trying to make a Rochefort 10 clone tomorrow and am a little confused about the exact terminology used in the Beer Captured book. I spent $90 on ingredients at the local homebrew store so I wanna make sure I don't screw this up. The book says:

"Remove the pot from the heat and steep at 150 degrees for 30 minutes. Strain the grain water into the brew pot. Sparge the grains with 1 gallon of 150 degree water."

The concern comes in at "sparge the grains with 1 gallon..".. Does this mean just pour 150 degree water (prepared in another pot) on the grain bag into the big brew pot?

Any extra suggestions or tips on this recipe would be welcomed.

Yup, you got it. Take the 1 gallon from another pot and just pour it onto the grain bag, let it leech out, and add that to your brewpot. Essentially, you're just washing out any starches and sugars that didn't get into the water when you steeped. What is the recipe?

If you don't have another pot, you can use a ladle and sparge using the water in the brew pot you steeped the grains in.

It's a big beer (for a presumed first). You'll want to give it some time to age.

It's not my first homebrew but it's my first not from a kit and it's definitely the most complicated brew I've ever done. I was under the impression that this brew would take a few months to ferment in the secondary fermenter but the book says 6 weeks.

beer never should 'ferment' in secondary. secondary is for clearing the beer, and can be done for bulk aging as well.
Primary is when all fermentation should start and finish.