Note: The structure of your communications plan is better if it's not dictated by a rigid template. A good communications plan format will let the planner use the cintent they need to and not make them force unnecessary sections into the plan.
SUMMARIZE
Outline the nature of the announcement(s) you plan to make. You'll flesh out your messaging and tactics later so don't worry about those now.
You're done most of the work for this section already-don't reinvent the wheel. Pull much of the content for this from your earlier analysis. Treat this as an executive summary of what you've already written.
KEEP LT SIMPLE
while you've waited until late in the planning process to identify the announcement you're making in all Likelihood this will be the first thing that executives reading and approving your plan will read. As such, you need to capture exactly what's going on succintly.
Try to identify the announcement you're making and why you're making it in one or two sentences
and in [lain language.
Remember: The executives haven't had the benefit of doing the background research you've done.
MAKE THE LINKS
You've already identified the context for this initiative; use that to briefly summarize here how this fits within your organization's broader activities.
BE HONEST
Don't "spin" youreslf. lt can be tempting to sugar coat what you're doing in the plan, to try and give "good news," but you won't do yourself any favours by doing that. Call a spade a soade while you're planning and you'll do better in the long-run.