I need to start customizing Jira such as auto-populating fields based on transitions, make some fields read-only in certain transitions, etc. I've had difficulty finding the right documentation to get me started. The getting started Rest API docs don't point to the correct version of Jira I have (v7.7) and links in them such as the "Getting Started" and "JIRA Rest API Overview" don't work. I'm not sure if I should implement a post function webhook or create my own plug-ins to accomplish what I need. I've installed JDK and Attlassian Plugin SDK but still lost on where to start. Any help getting me started would be appreciated. I know what I want to do just don't know how to get started.