In Qlix you are able to assign a room to a class or to individual lessons. Room allocated to an individual lesson will override the room set at the class level. This is useful if you, for example, teach 'Year 7' in 'S1' for all lessons except one lesson a week where you teach them in 'S4'.
You are able to see the room allocations from the timetable button in the bottom right corner, or by pressing the 'more' button for the individual lesson in the home or diary pages.
To allocate a room to a class, go to settings -> academic year -> classes, then click on the edit icon on a class. From here you can populate the room field in the bottom of the left column.
To allocate a room to an individual lesson, go to settings -> academic year -> timetable -> edit timetable, then click on the dots by the lesson. From here you can populate the room field.