in LW go 1)tools 2) options 3) sharing 4) add. This will allow you to browse and add folders you would like to share.

As to the 2nd question I'm not sure. I change the save to location to keep my files types separated. Videos in one folder, music in another. Books or Articles in another. I generally save to a specfic
location which isn't shared. This way I can preview the files to make sure they are of the quality and content I wanted (Not a mistitled or fake file). Then I drag and drop to the correct folder.