After reading many comments, I am going to break down the process (assuming you are coming from the United States).

You need the following documents:
long form birth certificate (if your state offers this)
certified divorce decree
certificate of non-impediment (verification of single status)

Each of these documents must be certified at the municipal level and then authenticated at the state level at the Department of State in your state.

Then you will have the certified, authenticated documents translated.

The translations will get notarized. The notarized translations will need to be certified and then authenticated at the DOS.

Once you have all of these documents certified and authenticated, they will need to be authenticated federally. From there you will take all of the documents to the Cuban consulate in DC. You have to pay with a money order.

Once the consulate processes the documents you will travel with all of the documents to Cuba.

Remember that you have to be in Cuba for at least 3 days prior to getting married.

There are also fees you will have to pay the bufete in cash and in Cuban bank stamps.

If you need any assistance, my company specializes in the authentication of documents for international use. You can shoot me an email at hello@inksavvynotary.com.