How to set up gnome-screensaver?

I am running Ubuntu GNOME 15.04 and I have install gnome-screensaver, however after doing some searches through my system, and my system settings, I am unable to find any configuration settings for this screensaver. And when I run it in Terminal I get:

** (gnome-screensaver:20082): WARNING **: screensaver already running in this session

So how do I configure it?

OS Information:

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 15.04
Release:    15.04
Codename:   vivid
Flavour: GNOME
GNOME Version: 3.16

Package Information:

gnome-screensaver:
  Installed: 3.6.1-0ubuntu16
  Candidate: 3.6.1-0ubuntu16
  Version table:
 *** 3.6.1-0ubuntu16 0
        500 http://archive.ubuntu.com/ubuntu/ vivid/main amd64 Packages
        100 /var/lib/dpkg/status

Gnome Settings

You can control the screensaver via Settings > Background, sorry but there are no more options in the GUI.

and via

Settings > Power

Tweak Tool

A little bit more options are in the Gnome Tweak Tool

gsettings or dconf-editor

And all options you can access via gsettings. Here is a list of all available keys for the screensaver

% gsettings list-keys org.gnome.desktop.screensaver
picture-opacity
logout-enabled
lock-enabled
logout-delay
embedded-keyboard-enabled
primary-color
idle-activation-enabled
secondary-color
logout-command
color-shading-type
embedded-keyboard-command
show-notifications
picture-options
lock-delay
show-full-name-in-top-bar
picture-uri
status-message-enabled
ubuntu-lock-on-suspend
user-switch-enabled

and for the power management

% gsettings list-keys org.gnome.settings-daemon.plugins.power
button-power
critical-battery-action
percentage-low
priority
lid-close-suspend-with-external-monitor
idle-dim
button-hibernate
sleep-inactive-ac-type
button-sleep
button-suspend
sleep-inactive-battery-timeout
time-low
lid-close-ac-action
notify-perhaps-recall
percentage-critical
percentage-action
sleep-inactive-battery-type
time-action
lid-close-battery-action
idle-brightness
sleep-inactive-ac-timeout
time-critical
active
use-time-for-policy

gnome-screensaver-command

To control the gnome-screensaver you have to use

gnome-screensaver-command

From man gnome-screensaver-command

SYNOPSIS
       gnome-screensaver-command [OPTION...]

DESCRIPTION
       gnome-screensaver-command is a tool for controlling an already running instance of gnome-screensaver.

OPTIONS
       --exit Causes the screensaver to exit gracefully

       -q, --query
              Query the state of the screensaver

       -t, --time
              Query the length of time the screensaver has been active

       -l, --lock
              Tells the running screensaver process to lock the screen immediately

       -a, --activate
              Turn the screensaver on (blank the screen)

       -d, --deactivate
              If the screensaver is active then deactivate it (un-blank the screen)

       -V, --version
              Version of this application