"She is a little tired and wants to sleep."
Translation:Ella está un poco cansada y quiere dormir.
'Ella está cansada un poco' would mean 'She is tired a bit', but the sentence is asking for 'She is a bit tired', so you must use' Ella está un poco cansada'. You may have been confused because normally you put adjectives after the noun, but 'un poco' isn't an adjective, so it can come in front.
Usually when referring to permanent things, we use "es". And for referring to temporary things like feelings or emotion we use "está". Like in this case "she is a little tired", which will likely to go away after sometime. Tiredness is not the permanent thing here. Hence está is used here instead of es. Example for es can be given like this. "Ella es mi hija" - "she's my daughter", which is pointing to a permanent fact.
I find that if ive made a mistake with another word, duo will use a word i havent been taught. I cant say what made duo offer harta, but a possible mistake might be typing ella es cansada pequena, and duo would try to fix the sentence with harta instead of está and un poco.
What in the world does "se desea" mean?!?!? I put "Ella está un poco cansada y necestitas (yes, I realize this is "needs" not "wants") domir. Instead of correcting me with "quiere", Duo said I should put "Ella está un poco cansada y se desea dormir". I'm so confused right now, should I be using "se desea"? Is that a different translation? Would love an explanation or something.
There are many times modifiers actually go in front of a noun. Rules are meant to be broken after all.
Ex, when you say "muchas gracias" you are essentially saying "much thanks" and putting the modifier in front. But there are many, many other times it will happen. Perhaps this will help.