Thats a big question. Before I start writing a huge boring post, could you explain a little more of what your trying to do?
Do you mean your trying to stream Amazon Prime through your Wii? Or do you mean your trying to play movies that are on your computer and see them on your Wii/TV?
If you just mean Amazon Prime, first make sure your Wii is online. Then register your Wii to your Amazon Prime account.
I can respond with additional instructions depending on your response.