What is your story about? Is it about four kids who go on an adventure together, or is it about the contents of a boy's room? Most likely, your story isn't about either of those things. But, if your story is about four kids who go on an adventure together, then you really shouldn't worry too much about the contents of one of those kids' rooms.
It is easy to get bogged down in details. Some particular thing holds your focus and you spend lots of time on that one thing, and it may be good, but it may also be completely irrelevant. I've mentioned plenty of times that stories will easily be rewritten, or at least heavily edited as it goes through the creation process.
Focus on the biggest picture first. Once you have an idea of the grand scheme of things, work on the next layer down. Maybe you would consider character qualities and relationships. After that, go to ancillary characters and scenes that connect the main points. It will not be for a while that you are looking at what color wallpaper somebody has, or the words you will be using to describe that color.
Again, what is your story about? If you can answer that, then start working on the real point of the story. If you don't know what your story is about, what kind of story do you think you have?