Download jPort package (jPort-[version].zip) using the jPort download link on the top-right. Unzip this file in any place.
To launch the jPort portable desktop, click "jport.jar". Java 7 and above should be installed. You will see the jPort menu to the right of your screen. Click on an icon to launch a selected program.
Alternatively, run the program on Windows by clicking the file "run.bat". For Linux or Mac OS, run "run.sh". Now you can copy the installation directory to a USB flash drive.
This step installs a demo jPort version. You need to activate it as described here
You can install more applications from Portable Java Program portal (PJP). Simply open "Options " → PJP Manager".
You will see a pop-up window with available portable Java programs. Select needed program and click "Install". You can also remove a program by clicking "Remove". The program will be removed from your local installation.
This window also allows to search for a program. This can be done by typing a name in the search field at the top of the window and by clicking [ENTER].
All preferences and data files will be stored on the same USB flash drive. However, you can also use the host computer file system
You can also add a new application to the jPort menu (in the PJP format) as "Options" → Open PJP file"