Dear client,
After analyzing your requirements and the space for the proposal I designed the following room that I believe will satisfy all your necessities.
The room has now three spaces to use :
1-ENTRANCE DESK & TOP LIBRARY:
This place can be used for kids to study or draw . The top Library can be were books that are not much at use are stored. Drawers beneath the desk allow pencils and other school items to be stored as well.
2-LOUNGE CHAIR:
This is were you can sit back an enjoy a book with a great light given by a floor lamp. It is also a place where you can sit and read a book to kids while they lay on the sofa.
3-SOFA-LIBRARY:
This is a magical place inside a wooden box where there is no excuse you can find not to lay down and read a great book . There are wardrobes with hidden books and drawers to store as many books and papers as you like. There is also place for books under the Sofa.

Radiator is in the same place covered by a wooden perforated panel that allows heat to get to the room. I chose to lower the ceiling by make a false ceiling to 2.60 m . By making this it will be easier to distribute light to all the spaces and it will also make the space a little bit more comfy. I also changed the window to a 1 sheet aluminum one to allow more light to come in , this is of course if the building allows you to , it is not that important to the project itself, meaning it can be made with out changing it but in m opinion the aluminum window is better ( it will help maintain temperature in the room as well as keeping the room more quiet from outside noises).

Hope you like the project as much as I did,
Regards!