Your setup is complete.
At this point, you can optionally install Java in Wine (see wineTricks) or make sure that your system is up to date with Java (native to Linux) and update your shortcut to call the Java launcher directly (see Creating a Launcher Script below). If you decide to install Java within Wine, your gameplay shortcut should be jlauncher.exe This executible is a wrapper for calling Java to run launcher2.jar
Creating a Launcher Script
You may want to setup a desktop script to run the Java launcher directly, instead of having to install Java within Wine. This is the recommended method of running Istaria, but has a small manual step to implement. Create a file on your desktop called istaria.sh - then open the file using a text editor (gedit or vim).
Add the following lines:
cd "/home/<YOUR USER>/.wine/drive_c/Program Files/istaria"
java -jar launcher2.jar
The following information may be out of date, but is included for completeness.