They know what you're asking. I doubt anybody online is going to say, "Sure, I have guns at my home - come to my home, guy I met on the Internet!" Ask at local clubs or local instructors if they'll walk you through the practical. Its easy money for them - quick $40/test for the challenge and say $25/50 for the practice round. All with no expense for them.
I challenged the courses successfully, but I had a good setup:
I didn't want to wait until the next course I could register for (+2 months) so the instructor gave me the name of one of his buddies who supplies the guns for the course. I met the buddy and he guided me through the practical tasks as we practiced with real guns.
The following day I met the instructor at his home, wrote the test and then did the practical portion on the very same guns I practiced with the day before.
As mentioned, you'll have to do a bunch of things: ID cartridges (e.g. show me a 3" shotgun shell, show me a slug, show me a .45, show me a semi-jacketed round, etc.).
Once you do that, you pick up the gun he tells you to (e.g. pick up the pump action shotgun) and prove it safe, including putting the safety on. Then he'll tell you to load two rounds, and chamber one of the rounds. Then clear the firearm.
Lather rinse repeat for a few of the other firearms, but for some of them, you will need to demonstrate a shooting position (e.g. the kneeling position, or the one handed stance for handguns, etc.). Then he'll ask you to pretend you are crossing a fence while hunting, so you clear your firearm, push it under the fence, cross the fence, then prove it again.
Then you're on a range, where someone calls a cease-fire. Stop shooting, make your gun safe, step behind the safe line.
After that, you're done shooting at said range, so now you have to make your gun legal for storage/transport in a case, including the "ATT" and locking the case...
For me, the hardest thing was to maintain muzzle control of the handgun during the lock-up stage.
Short of pointing the firearms at your instructor (auto-fail), it's actually fairly difficult to fail.
g'luck
P