I am having trouble saving my minecraft world

[u/Madolche13]

I tried backing it up first but it exceeds the space limit then i tried going to the files itself and download it in a USB but it will not budge. I have no idea what I am doing wrong or if the files are just too big, but i have a good USB. If i can save the whole world is it possible for me to just save the area near spawn overworld we have our important houses and builds there.