I logged in to iTacit, but it will not let me click on anything.

You may have a touch screen enabled computer which currently conflicts with the use of iTacit.  To have the touch screen option turned off, please follow these steps...

To disable the touch screen in Windows 10, press Windows+X on your keyboard to access the Power User menu, then select “Device Manager”. In the Device Manager, click on the right arrow to the left of Human Interface Devices to expand the list  You should be showing something related to your touch screen in this area.  Click on it and select 'Disable'.