Just double click on the .JAR file to run it.

However, in teh case it doesn't work:

In order for the batch file to work, the "java.exe" program
must be present in your path environment.

Also, if you execute the batch file from a drive other than
your system drive, the program may not start properly, in
that case you should run it manually from the command prompt
using "java -jar seg2106lab3.jar" from the actual path where
the file is contained.