The certification steps for cdf Hainan Ferry Islands are as follows:

1. Prepare a valid ID card, passport or other valid travel documents.

2. Prepare a travel certificate issued by Hainan Ferry Company to prove your intention and purpose of travel.

3. Prepare a document that confirms your identity, such as a copy of your passport, driver's license or credit card.

Please ensure that all documents and information provided are true and valid in order to successfully complete the certification.