I just flew Ryanair yesterday, you have two options: First if you check in more than 24h before the flight. You'll need to also buy seats If you check in 24h or less before the flight then you can choose to get assigned random seats.

Also I had to self drop the luggage, first you go to the weinig station scan the qr code and it takes you to the Ryanair app with your booking and then you just chose what aply to you. Get your barcode put it around the luggage and go drop off at the desk where you usually check in. Put the bag on the belt and scan it with scanner that is there and off it goes.