These rooms for families, couples and groups should be reserved in advance. But as a general rule, anyone can show up on a walk-in basis and hope to get a bed. Generally, reservations are not required, but I do recommend that you have a reservation for your first night in Europe or any city that you plan on arriving in after 6 or 7 p.m. Also, if there is a festival or major event going on in the city, you would be best advised to make a reservation or plan on staying in another city nearby. This is a computer system available in larger hostels so that you can reserve and pay in advance for a room in another hostel within the network of hostels in the system.
Most hostels have a community restroom or water closet.
You will have to walk down the hall to the showers and maybe even wait in line. Some places charge extra for hot water. These details should be in your guide book, but you may want to ask at the desk to be sure. Usually breakfast is included in the price of the room for the night. A typical hostel breakfast may offer bread, butter, jam, and coffee or hot tea.