Manage the default directories in Nautilus

Just edit the following file: ~/.config/user-dirs.dirs

XDG_PUBLICSHARE_DIR="$HOME/Public"
XDG_DOWNLOAD_DIR="$HOME/Downloads"
XDG_MUSIC_DIR="$HOME/Music"
XDG_VIDEOS_DIR="$HOME/Videos"
XDG_DESKTOP_DIR="$HOME/Desktop"
XDG_DOCUMENTS_DIR="$HOME/Documents"
XDG_TEMPLATES_DIR="$HOME/Templates"
XDG_PICTURES_DIR="$HOME/Pictures"

Version context

This procedure describes the software and the environment available at the time of its publication. The packages, interfaces, and repositories mentioned may have changed or disappeared; first check the system version and its support level.

cat /etc/os-release
uname -r

Work on a backup or a snapshot, note every modified file, and prepare for rollback. For a current workstation or server, prefer signed packages from officially supported repositories.

Reference: official Ubuntu lifecycle.