I'm trying to write my first selenium script using LISA/DevTest but don't know where/how to get started on it. As I know that we write the code in Java but here we try to do in JSON script. Can anybody let me know how I can get started on the same.
Did you check out Create and Export a Selenium Builder Recording - DevTest Solutions - 9.5 - CA Technologies Documentation? The recommended way to create Selenium test cases in Application Test is to record the test in Selenium Builder and import the recording from JSON file as Selenium test steps or as a Selenium script. The link includes a short video about the integration of Selenium Builder and Application Test and how to create and import Selenium recordings into Application Test. This should give you a good learning experience on the topic.
Edit: There also was a recent webcast on the topic. Please see Webcast Recap: DevTest & Selenium .