Install tkinter for Python
It is not very easy to install Tkinter locally to use with system-provided Python. You may build it from sources, but this is usually not the best idea with a binary package-based distro you're apparently running.
It's safer to apt-get install python-tk
on your machine(s).
(Works on Debian-derived distributions like for Ubuntu; refer to your package manager and package list on other distributions.)
Actually, you just need to use the following to install the tkinter for python3:
sudo apt-get install python3-tk
In addition, for Fedora users, use the following command:
sudo dnf install python3-tkinter