kdcamper - nice choice. Before I shoot you the CHF info - let me say it again - Fight the urge to go and ensure the dealer does his thing. As I learned and as I've advise spend $300 and buy a hardwired surge protector. I bought the Progressive Industry EMS-LCHW50. You've purchased a great house on wheels - spend another $300 to make sure flaky or fluctuating power at a campground doesn't fry your great gizmos. I'll also bet if you take it with you to walk through they'll install for free.
One more recommendation. Spend another $250 and protect one of the most important systems on your new home - tires. When I was pulling my TT I was constantly checking and worrying about my tire pressure - but I wasn't riding on them. After I began driving my home, I kept thinking having visions of blowouts while driving 70 mph down a busy interstate. I bought TST 507RV Tire Pressure & Temperature Monitoring System. No more blowout nightmares.
Now the simple question you asked about CHF. To boil it out, it simply acts to stiffen the torsion bars that generally control the side to side movement of your home. As I've come to understand, the chassis comes setup for general use and at the outside of the two holes of the torsion bar holes. The CHF simply shortens and consequential stiffens these torsion bars and thus reduces the side to side sway. Your new home won't seem to wander so much. Anyway there is LOT on this but this link comes with pics.
Cheap Handling Fix - Page 3 - iRV2 Forums
There are also some new driver videos and lots of tips. Forty years ago I drove a military heavy equipment transport (big a.. tractor/flat bed) but I'd forgotten one of the best tips. Don't drive looking at the immediate front of your coach - drive looking down the road a bit. Really stops the fidgeting.
Sorry for the elongate response but as you can tell I feel very strongly about the tire and electrical adders. Spending about $550 to protect your home and family is cheap.
Enjoy - we do!!!