New cargo Zeppelin uses HPE Helium Pressure Envelope - How do these work?

Factual Questions
1

Video here

At around 1:20 one of the engineers starts talking about pressurized helium bags and how that’s what makes it all work. Not understanding a bit of it.

I get that helium is lighter than air, but how the hell are pressurized bags of helium (assumedly heavier than air in that state) going to help this air cargo ship move around?

2

I’m at work, so I won’t check it out, but are you sure that link goes where you think it goes?

3

Compress the helium to control its levitation… to descend.
to float, go to the grotto, or expand the helium.

http://rt.com/news/aeroscraft-revolutionary-airship-cargo-187/