Two artifacts sit at the center of every CMMC Level 2 program, and assessors reach for them first: the System Security Plan (SSP) and the Plan of Action & Milestones (POA&M).
The SSP: how you meet each control
The SSP describes, control by control, how your environment satisfies each of the 110 NIST SP 800-171 requirements — the systems, the settings, the responsibilities. It is the story of your security program in one place. If it is vague or out of date, everything downstream is harder.
The POA&M: what is not done yet
No program is perfect on day one. The POA&M is the honest list of open gaps, each with an owner and a target date. Under CMMC, a limited set of items may sit on a POA&M at assessment time and must be closed within a defined window (the convention is 180 days). It is not a place to hide problems — it is how you show a credible plan to close them.
Why order matters
Draft the SSP early, even imperfectly. The act of writing it surfaces the gaps that become your POA&M — while they are still cheap to fix. See where your program stands.