There are two conjugation of '자유롭다', they are '자유로워' and '자유로우니'.
'자유로운데' is combined with one of the conjugation '자유로우니' and an ending '-는데'
Also you can combine the verb '자유롭다' with an ending '-지만'. It is combined like this; '자유롭지만'
The sentence can be translated like "바람은 자유로이 부는데" or "바람은 자유롭게 부는데" as well.
'자유로이' and '자유롭게' are derivatives of '자유롭다'. They are used as an adverb.
By the way, 이해하지 '못 하겠어요.' is the proper expression :)
'-하지 않는다' means that you don't do something on purpose :)
Hope it helps! :)