Similar process with the full immersion brewing, but slightly different as it has a filter like you mention, so you are meant to use a finer grind than for french press and a very short total time of immersion. Something like 20 seconds of extraction and 30 seconds of plunging. The fine grind and seal on the plunger also gives you a bit of pressure, they call it "espresso" but it's not really the same as the high pressure that an espresso machine puts out. What you end up with is really concentrated so you can drink it like espresso or dilute with more hot water to make a sort of americano drink.
I already had my afternoon cup of french press, a decent cup of Brazilian Monte Carmelo, but I wanted to try this thing out so I got my boss to be a guinnea pig. I used my Kyocera CM 50 (ordered along with the Aeropress) set to 2 notches (one step coarser than the finest it will go),some Ethiopian Harrar beans, 20 seconds immersion, but the plunge was very hard, and took me longer than directed. He claimed it was really good so I don't know if the long time over extracted or not. Next time I'm going to go to 3 steps from finest, which should be a bit finer than auto-drip grind.