How do you migrate a Jenkins pipeline to Bamboo?

A migration is mostly a mapping exercise between two similar concepts expressed differently, plus a re-plumbing of credentials and triggers.

1. Map structure — Jenkinsfile stage blocks map to Bamboo stages; parallel Jenkins branches map to parallel jobs within a stage; individual sh/bat steps map to Script tasks.
2. Rebuild plugin functionality — a Jenkins plugin step (e.g. a specific deployment plugin) usually has no direct Bamboo equivalent, so it's replaced with an equivalent Script task or, where available, a matching Bamboo task type.
3. Move credentials — Jenkins credentials become Bamboo Password-type variables, referenced the Bamboo way rather than via Jenkins' credential-binding syntax.
4. Reconfigure triggers — Jenkins webhook/SCM triggers are replaced with Bamboo repository triggers pointed at the same repository.
5. Express the result as Specs — writing the new pipeline as Bamboo Specs (rather than clicking it together) keeps it reviewable, similar in spirit to how the Jenkinsfile itself was versioned.
6. Run both in parallel briefly — validate the Bamboo plan produces identical build/test outcomes before retiring the Jenkins job, using plan branches to test without touching the main pipeline.