Start with scope and context: determine what is in the ISMS, what interested-party requirements apply, and which interfaces and dependencies matter. ISO/IEC 27001 requires the organization to establish, implement, maintain and continually improve the ISMS, so the roadmap should begin with those boundaries.
Next, define the policy, roles, and responsibilities, then set information security objectives that are measurable where practicable. From there, move into risk assessment and risk treatment, including the Statement of Applicability and the risk treatment plan, before shifting to operation, monitoring, audit, management review, and continual improvement.
The order in the standard is not the order in which implementation has to happen, but a visitor still needs a clear first, next, and last step. Use the sequence below as the working roadmap for ISO/IEC 27001 implementation.