The "Start\ Ganib.sh" is present inside the directory "Ganib-3.3-with-jre", so you need to change directory in the terminal with below commands and apply permissions too. So the sequence of commands you will be executing to start Ganib is:
1) cd ~/Documents/Ganib-3.3-with-jre (To Change the directory)
2) ~/Documents/Ganib-3.3-with-jre$ chmod +x Start\ Ganib.sh (To Apply the permissions).
3) ./Start\ Ganib.sh (To Start Ganib application).
Now, Ganib will start properly.
If you are still facing any issues regarding the installation or any other functions with Ganib, Please feel free to contact us. We are happy to help you.
Happy Using Ganib.