When you travel with Ryanair, you need to check in online and print your boarding pass/es before arriving at the airport. This is to avoid costly fees for getting your boarding pass at the airport.
Go to Ryanairs website
Click "Check-in" (top-middle of the page).
Choose "Get booking now" (No account).
Enter your referencenumber (specified on flight ticket - 6 digits or letters). Enter the email address (specified on flight ticket) and click OK.
In the next step, you can administer your flight booking. Check in and print your boarding passes for both your out- and inbound flights. It is also possible to use Ryanair's app to check in. After that, you have access to your boarding passes on your phone. You can download the app from the App Store or Google Play store. Please read the instructions from Ryanair carefully.
Note: You will get assigned seats if you check in from 4 days before up until the date of departure. From 30 days to 5 days before the departure, it is still possible to check in, but you will have to pay a fee for seating.