This is a guide on how to fill in the Cuban Customs Declaration form which will be handed to you by the cabin crew on your flight.
Only one form needs to be completed per family, but the questions apply to both you and any family members travelling with you.  

Here is a link showing the front page of the card:

Cuban Customs Declaration Card (front) 

Date of arrival:     Day....Month.....Year (the last two digits of the year is all that is required)

Your first name and last name (only the lead family member writes his/her name here)

Birth date of the person whose name was entered

Gender (F or M)

Passport number

Nationality

Your country of residence


Boarding country (the country where you boarded the plane for your flight to Cuba)

Airline
you flew with into Cuba.

Your flight number

Number of relatives travelling with you

Passport numbers of the other family members
(there are only two lines, so you may need to squeeze more than one passport number on each line if you have more than two other family members travelling with you)

Did you or any of your relatives check any piece of unaccompanied luggage.  Yes or No.   Answer will usually be No.

The import of hard currency is unrestricted.  Passengers are required to declare the total amount of money they carry if it exceeds 5,000 USD or their equivalent in other hard currency, whether in cash or negotiable instruments.  If, upon departure, you intend to take with you any amount of money in excess of $5,000 ortheir equivalent in other hard currencies when you leave Cuba, you must inform the Customs Inspector.
So, if you and your relatives bring into Cuba LESS than $5,000 USD or its equivalent leave this section blank

Mark with an X if you are bringing in your luggage or carrying any of the following items:

-Weapons (firearms, sharp instruments or others) and ammunitions

-Drugs, narcotics drugs psychotropic substances. It does not refer to any prescription medications you may have brought with you.
.
-Live animals

-Satellite communication equipment, Walkie Talkies, or others.  
Do not list your cell phones or iPads.

-Animals or vegetable products

-Samples or other items for commercial purposes

-Pornography


If, as is most likely, you have none of the items listed above, leave the boxes blank

Besides your personal belongings, you bring in some miscellaneous such as footwear, clothing, foodstuff, personal hygiene and household goods, custom jewellery, lingerie, toiletries and other related articles that are worth:

Leave this blank unless you are bringing in any of those items as gifts for Cubans.  If so, you should enter the total value of the things you are bringing to give away to Cubans as gifts.

Here is a link showing the back page of the card:

Cuban Customs Declaration Card (back) 

List the equipment and items (electrical appliances and others) other than miscellaneous that you bring with you

Do not list your cell phone, iPod, MP3, laptop, camera etc.  Only list electrical appliances such as microwaves, toasters, mixers, blenders, fridges, air conditioners, etc.    If you have no such things you do not complete this section. If you do, list the item, amount and value.

Do you have anything else to declare at the Customs?

If you checked the NO box (as is most likely) you are a Green Channel  passenger, 

Once you have collected your luggage, sign and hand your Declaration to the Customs Officer at the exit door.   If you checked the YES box, sign your Declaration and approach the Customs dispatch area.