Gunesh,
If you are generally interested in open source, find a project that you would like to contribute to - maybe that is GNU Radio, maybe something else you find along the way. Familiarize yourself with the software and reach out on the chat asking for ways you can get involved. This might be at first improving documentation or fixing minor issues. There is a tag in the github which is "good first issue" which can be good to tackle. Once you are ready to submit a pull request (contributing your code back to the main repository), myself or others can help guide on some of the particulars.
Josh