I can forgive ignorance easily, as I have plenty of my own. What I cannot forgive is Choosing Ignorance 
To open a terminal, press all at the same time Ctrl Alt and t
ctrl+alt+t
Enter into it
pkexec thunar
or as Carmar said
sudo thunar
Both will achieve the same goal, but pkexec is aimed toward using ‘sudo’ to operate a Graphical Application.
The command ‘sudo’ stands for SuperUserDO as in, Do-this. SuperUser is the user account to access Root.
The way Linux file system is structured is similar to your Android Phone. This makes sense since Android is based on Linux, though it has diverged with ARM to become different enough to no longer be interchangeably compatible.
You operate normally from /home/$USER/
where $USER is the username you had set up during installation. This is abbreviated, in terminal and elsewhere, to ~/. You may often see a path specified on the forum to go to your pictures folder looking like ~/Pictures.
The system files are elevated above this Home Directory. Just like your droid, this is to keep them a bit isolated to prevent system damage from user mistakes. This is just / or Root and can only be changed with a password. That is the root password you also set up during installation and the same one you log in to your desktop after bootup with.
You are spot on that the option to create a new folder was greyed out because you were not operating with Root Privileges.
When you “pkexec thunar”, you will get a password prompt. Enter that, then navigate to /etc/X11/ and from within the X11 directory, right click, choose create new folder, rename that new folder from Untitled to
xorg.conf.d
Double click to enter it, then right click, create new document and name that
40-synaptics.conf
Once that is created, copy the above code in the previous post and paste it into the new created 40-synaptics-conf file and save it.
Then log out and back in to test.
If that does not work… when you move to log in; tap-touch is nto working, then log in and open terminal (ctrl-alt-t) and enter into it
sudo apt install xserver-xorg-input-synaptics
Check the terminal output and make sure it installed successfully.
Then log out and in to test.
Makes sense. Could you post a screen shot of both theme usage on the calendar? You can take a screenshot with one button push by hitting the prt-scrn key. It saves to your Pictures folder automatically.
Screen shots can be uploaded to the forum with either Markdown language tags or by hitting the Image icon on the toolbar over the posting text area when composing the post.