In order to enable the click on tap and vertical and horizonal scrolling functions for your touchpad, it will be necessary first open your terminal in order to open and then edit the synaptics configuration file.

Open the Synaptics Configuration File

The syntax the command to edit the synaptic configuration file is:

sudo [text editor] /etc/X11/xorg.conf.d/50-synaptics.conf

To use nano (the default text-based terminal editor) enter the command:

sudo nano /etc/X11/xorg.conf.d/50-synaptics.conf

Otherwise, you may find it easier to read and edit the file by using gedit, which will open the configuration file as if it were a document. To use gedit instead, enter the command:

sudo gedit /etc/X11/xorg.conf.d/50-synaptics.conf

Enable Click on Tap, Vertical and Horizontal Scrolling

Once the synaptic configuration file has been opened, replace the content of this file with the following:

Section "InputClass"
	Identifier "touchpad catchall"
	Driver "synaptics"
	MatchIsTouchpad "on"
	Option "TapButton1" "1"
	Option "VertEdgeScroll" "1"
	Option "HorizEdgeScroll" "1"
EndSection

Once your amendments have been completed save your changes and close the configuration file by:

nano: Press CTRL and 'x' to exit, 'y' to save, and <enter> to finish, or
gedit: Select the 'save' option and then close the window.