Implement
We own the build, and the operation keeps running while the ground changes.
The question this phase answers
How does the roadmap become real without stopping the business? Implementation is sequencing under load: infrastructure, cloud, security, identity, software, and integrations, in the order the design set.
What you receive
The system built, migrated, tested, and documented: code, decisions, and how to operate it. Documentation is part of delivery, not an extra, because the business must own the system rather than depend on whoever built it.
What you decide with it
Acceptance with evidence: what was delivered, what changed from the plan and why, and what the operation now depends on. Nothing arrives undocumented.
What this looks like in practice
Working increments the team can use and react to, instead of a reveal at the end. Real life corrects designs; short cycles let it correct them cheaply.