What passenger information is required for Ryanair Online check-in?

I have booked flights for 25 of us to Spain with Ryanair and am starting to gather information for when we online check in. I have been told I need everybody's passport number,expiry date & date of birth. Is this correct or do I need to provide anything else?? Can't check on the website until 15 days before departure and i have a lot to of information to gather!