JIRA and Scrum are great ways to facilitate agile development but it's not bidirectional. I usually push rigid Scrum on teams if I think they lack discipline or experience. Follow the textbook until you understand why. When I'm working with smart veteran devs who know exactly why and how agile works, we can afford to be more freewheeling.

I think agile is fundamentally simple. The essence is the continual improvement. How that translates into a working process (like when do I write tests and who updated the docs) are going to vary project to project.