As a Team or School Leader (CRO, HoP, HoD, etc.) you are free to design Gameplans for your Team. It's your job to understand the missions (=Activities) that members of your Team are regularly involved with, along with the intricacies of the way your Team works, and to thus organise the pieces accordingly. You should get the HoP's input when you are thinking about a new Gameplan, to ensure that it follows basic principles for time tracking, deliverable tracking, status tracking, etc.
Once drafted, you must seek approval from Management for ratifying Gameplan changes. In other words, you can design things yourself and you're responsible, but you must run your proposal by the Management team before your Gameplan becomes law.
You are responsible for documenting your Gameplans. Keeping that documentation up to date. Soliciting feedback on it from your Team members. Implementing continuous improvement to it.
When designing Gameplans, follow our cultural principle of: "people over processes". Design your Gameplans to be as lightweight as possible. A Gameplan should set clear and measurable outcomes, document responsibilities and document communication protocols, and not much more. Leave as many of the bits in between as undefined so you can, to afford your team the freedom to use their brains. Don't script every interaction.