welcome Upeksha !. Here you can find instructions regarding contributing https://taverna.incubator.apache.org/download/code/#contribute-to-apache-taverna
In this case you have to build taverna-common-activities <https://github.com/apache/incubator-taverna-common-activities> and taverna-workbench <https://github.com/apache/incubator-taverna-workbench> modules. Here you can find how to run the workbench in developer mode http://dev.mygrid.org.uk/wiki/display/developer/5.+Running+Taverna+from+Eclipse. You will find that the package names are changed and that is because this tutorial is outdated. But still it is useful. First try to regenerate the problem and then try to solve it. Good luck and if you need any help please ask. regards, Thilina.
