Here is my 50-synaptics.conf

# Example xorg.conf.d snippet that assigns the touchpad driver
# to all touchpads. See xorg.conf.d(5) for more information on
# InputClass.
# DO NOT EDIT THIS FILE, your distribution will likely overwrite
# it when updating. Copy (and rename) this file into
# /etc/X11/xorg.conf.d first.
# Additional options may be added in the form of
#     Option "OptionName" "value"
#
Section "InputClass"
                Identifier "touchpad catchall"
                Driver "synaptics"
                MatchIsTouchpad "on"
# This option is recommend on all Linux systems using evdev, but cannot be
# enabled by default. See the following link for details:
# http://who-t.blogspot.com/2010/11/how-to-ignore-configuration-errors.html
#             MatchDevicePath "/dev/input/event*"
####################################
## The lines that you need to add ##
# Enable left mouse button by tapping
Option    "TapButton1"    "1"
# Enable vertical scrolling
Option    "VertEdgeScroll"    "1"
# Enable right mouse button by tapping lower right corner
Option "RBCornerButton" "3"
####################################

EndSection

Section "InputClass"
                Identifier "touchpad ignore duplicates"
                MatchIsTouchpad "on"
                MatchOS "Linux"
                MatchDevicePath "/dev/input/mouse*"
                Option "Ignore" "on"
EndSection

# This option enables the bottom right corner to be a right button on clickpads
# and the right and middle top areas to be right / middle buttons on clickpads
# with a top button area.
# This option is only interpreted by clickpads.
Section "InputClass"
                Identifier "Default clickpad buttons"
                MatchDriver "synaptics"
                Option "SoftButtonAreas" "50% 0 82% 0 0 0 0 0"
                Option "SecondarySoftButtonAreas" "58% 0 0 15% 42% 58% 0 15%"
EndSection

# This option disables software buttons on Apple touchpads.
# This option is only interpreted by clickpads.
Section "InputClass"
                Identifier "Disable clickpad buttons on Apple touchpads"
                MatchProduct "Apple|bcm5974"
                MatchDriver "synaptics"
                Option "SoftButtonAreas" "0 0 0 0 0 0 0 0"
EndSection