In this tutorial you will learn how to install XFCE desktop environment on CentOS 7.
CentOS 7 comes with Gnome desktop environment by default, which is heavier than XFCE and it doesn't run that smoothly especially if you are installing centos 7 on a computer with low specs.
Follow the steps below to install XFCE on CentOS 7.
Step 1 - Install EPEL release
Simply run the command below to install epel release, this repository contains all packages that we'll need to install XFCE
sudo yum install epel-release -y

Once epel has been installed, it should look like this

Step 2 - Install Window-x system
Once you've installed the epel release now you can proceed with the installation of Window-x system by running the command
sudo yum groupinstall "X Window system" -y

As you can see on the screenshot above Window-x system got installed correctly, now you can proceed to the next step which installs the desktop environment, in this case XFCE.
Step 3 - Install XFCE
Run the command below and grab a coffee :) as the setup might take awhile depending on your computer specs and internet speed.
sudo yum groupinstall "Xfce" -y

Starting the GUI
After you have successfully installed all the packages needed and XFCE desktop, you need to start the graphical user interface, in other words you are telling the os to start the GUI because there will be no gui loaded even after you have completed the 3 steps above, so to do this simply run the command
sudo systemctl isolate graphical.target

and you should see the display manager "gdm" window, shown as below

Next, enter your username and click "Next, then click to the gear icon and select "Xfce Session" to login to xfce

Final Step - Enable GUI on boot
This step is very important because to avoid starting gui manually each time by the command above, you can enable gui on boot, so when os boots up it will automatically start the gui also.
sudo systemctl set-default graphical.target

Now, you can reboot and login to your server, on this step you can choose to start with an empty panel or simply go with the default one by clicking the "Use default config" so you don't have to create an panel and adding items to it manually.

And that's it! Once you click "Use default config" button the panel shows up and the system is ready to use.

Conclusion
In this tutorial you learned how to install XFCE desktop environment on CentOS 7. Personally I like XFCE more because of performance and stability, I love it. However, that's just my opinion and it shouldn't stop you from trying gnome or other desktop environments.