To apply for an SSS calamity loan, you need to log into your My.SSS account on the SSS website. From there, navigate to the 'Loans' section and select 'Calamity Loan.' You'll need to provide the required documents, including proof of income and the calamity declaration from the government. It's important to check if you're eligible based on your contributions and the specific calamity. For more detailed guidance, you can visit the official SSS website or contact their customer service for assistance.