1. Download the package file
2. Decompress the file
3. Install the GUI version
4. Open the GUI

Download the package file

I cannot directly provide the download link because of the license issue. You may find the package file by your self

Decompress the file

tar -xvf PanGPLinux-5.2.6-c18.tgz

Install the GUI version

sudo dkpg -i GlobalProtect_UI_deb-5.2.6.0-18.deb

Open the GUI

The GUI will automatically launch after the installation completed, but will not persist. To reopen the GUI, run the command:

globalprotect launch-ui