A section labeled "Background" is customary but not strictly required. Background means background. Such a section is about the state of the world before your invention and does not mention or even hint at your solution.
It is a dangerous section because since by the definition of background it is presumed to be in the past and relevant. Anything in it might be interpreted as being "admitted prior art". Prior art just means things that are allowed to be used against you. To be prior art something must meet certain criteria in terms of dates, was it really a publication, was it really potentially accessible by the public, is it in the same or an analogous art? Or if you say it is prior art then it is prior art meaning it is usable against you even if it would otherwise not qualify as prior art.
Background sections set up the problem and discuss previous solutions. When the reader is finished with it they should understand the problem, think it is a real problem and be wondering how the heck you are solving it! If your background telegraphs your solution as they read it, then your solution will seem obvious.
Other problems with background sections include characterizing a specific reference as not covering something that it turns out it does cover. Then you are mis-directing the examiner "don't bother with XYZ, it doesn't deal with bird cages, only large animal cages." But you missed the mention of an interesting ostrich cage. If you dis someone else's solution you may inadvertently be limiting your invention. "ABC is a horrible solution because it has only one hinge." Your examples have two hinges which you think is best but you get a broad claim through that says "one or more hinges". Someone builds your idea but has come up with a really long or strong single hinge. Your claim reads on it - you've got them! But you deprecated something as being horrible due to having one hinge. It is easy for a judge to say that something you think is horrible certainly doesn't fall under any of your claims.
In the detailed description section you should give examples of how your thing is used. A concern is that you make clear whether or not you are describing something you have actually done or something that should work but you haven't tried.