If you are using the Xfce Desktop Environment, open Settings Manager and scroll to and open Mouse and Touchpad. You will see that you are in Devices. Make sure that your particular touchpad device is shown. Just below that you will see two tabs: Buttons and Feedback plus Touchpad. Open Touchpad and activate Tap touchpad to click if necessary and also make sure that the scrolling mode is set to Two-finger scrolling. This should work.
If you are not using the Xfce DE, then someone else will have to help you.
Good luck.
Lawrence