Same thing that Adam said, except that there is a flat spring-type lever at the front of the right seat track on most newer Beetles and Supers (both my '69 standard and '71 Super had them). I'll see if I can find a picture to post on the internet to show you where.
Yes, the whole seat comes out as a unit. Also, there is usually a big coil spring somewhere underneath attempting to hold it back. It is pretty easy to find and remove once you have moved the seat all the way forward.
Yeah, here's a picture. See the area circled in red? You have to push down on this spring release while sliding the seat forward.
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