gsettings utility provides a way to get to GSettings which is more or less like a Windows registry containing key value pairs.
GSetting values are different for each user. To modify or view values for a different user, launch a dbus session as the user via
# sudo -H -u lightdm dbus-launch --exit-with-session gsettings list-recursively
The amount of idle time before the screensaver starts is set using:
# gsettings get org.gnome.desktop.session idle-delay uint32 60 # gsettings set org.gnome.desktop.session idle-delay 3600
The amount of time before the screen is locked is set:
## Instantly locks when the screensaver starts # gsettings set org.gnome.desktop.screensaver lock-delay 0 ## Or a delay in seconds. Eg: 1 minute # gsettings set org.gnome.desktop.screensaver lock-delay 60