In my opinion, a cuckoo clock is a very detailed design, but you say you want a simple design for the room. When you say simple, are you thinking of no wallpaper, no wainscoting, and no accent color on the walls? It seems as if dark orange is a color you favor. I see it in art images and in your curtain color. If this was my space, I would paint all the walls one or two shades lighter than the beige of the sofa to keep the room as bright as possible because the room has no direct sunlight. I would paint the ceiling 1/4 (one part wall color to three parts white). I would use a satin or eggshell paint instead of matte, semi-gloss, or high-gloss paint. I see some discoloration on the wall behind the sofa where the brown color of the sofa frame has worn off onto the wall. I suggest attaching bumper dots or strips on the wood frame of the sofa (similar to the ones used to keep cabinet doors from making a lot noise when they are closed quickly). I would consider painting the sides of the column with the cuckoo clock brown to match the clock. I would do this to call attention to the clock. I would remove the orange curtains and replace them with floor-to-ceiling length draperies hung as close to the ceiling as possible to make the room seem larger and taller. I would change the drapery color to match the walls, perhaps in a muslin-like fabric, which is a casual fabric. I always take my art to a professional framer. I have conservation matting and museum glass used for my art. I would have the three images you have rearranged as a collage in a very large single frame with medium to wide matting between the images. I would have the mat and frame color(s) enhance the images, even if it is a color I might never have thought of on my own. I would hang it above the sofa. I would use the orange drapery fabric to make throw pillows for the sofas. You did not attach a photo of the flooring in the room. A medium tone floor is easier to keep looking clean than a light floor/rug or a very dark floor/rug. Other "Houzzers" will give you completely different ideas. Use the ideas YOU like and enjoy your home!

Dudes, that is a stock image from Dear Kids. That is not the person's room. Dear poster, It would help a lot if you showed readers the colour of the floor, trims, other furniture and even the ceiling. Too, it would be good to know what style of house you have and the other colours in your house. Why people who reply go to more bother than the person who asks the original question, I do not know.

if u like to paint the walls with light grey shade then it would be better to make the sofas white rather than a darker shade.

I would suggest u to go with white sheer and light grey curtains only. If u want want to play with bright colours then it is safest if u add them in form of accessories or decors, reason one being the space is small n it’ll look more crowded then. It’s better if u avoid orange n yellow in this bedroom at least. If u can give a better picture of the accent wall colour here it would be better. Then u could go with a darker shade of it to form the colour scheme. White+Grey+Purplish brown. That’s it.