[Haskell-beginners] Easier alternatives to existential types?

Hello everyone. I'm trying to write RIFF parser and can't decide what to do with "container" type. "Container" chunk should hold a header (two Word32's), a "type" (Word32 like "WAVE" etc) and a "list" of other chunks. Of course lists can't be used because we have far more than one chunk types. What can I do with this? I discovered existentials for myself recently, but those could be too hard for me yet. It feels like I'm missing something very obvious here. Thanks for attention. -- Emile.