The course is still missing grammar notes.
Polish verb are categorised in several declensions (depending on the source you can see any number from just 3 to over 50). Anyway, this is an example of the -e declension, which goes like this:
I kinda would put it this way: ą = American pronounciation of 'own' minus the n, kind of like what 'oh' sounds like, but still not quite. ę = eh-wn trying to emulate the 'own' pronounciation, again, this ideas with an American pronounciation.
That's the best way I can put it for you.